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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/bpf_lsm.h>
23#include <linux/skmsg.h>
24#include <linux/perf_event.h>
25#include <linux/bsearch.h>
26#include <linux/kobject.h>
27#include <linux/sysfs.h>
28#include <net/sock.h>
29#include "../tools/lib/bpf/relo_core.h"
30
31/* BTF (BPF Type Format) is the meta data format which describes
32 * the data types of BPF program/map. Hence, it basically focus
33 * on the C programming language which the modern BPF is primary
34 * using.
35 *
36 * ELF Section:
37 * ~~~~~~~~~~~
38 * The BTF data is stored under the ".BTF" ELF section
39 *
40 * struct btf_type:
41 * ~~~~~~~~~~~~~~~
42 * Each 'struct btf_type' object describes a C data type.
43 * Depending on the type it is describing, a 'struct btf_type'
44 * object may be followed by more data. F.e.
45 * To describe an array, 'struct btf_type' is followed by
46 * 'struct btf_array'.
47 *
48 * 'struct btf_type' and any extra data following it are
49 * 4 bytes aligned.
50 *
51 * Type section:
52 * ~~~~~~~~~~~~~
53 * The BTF type section contains a list of 'struct btf_type' objects.
54 * Each one describes a C type. Recall from the above section
55 * that a 'struct btf_type' object could be immediately followed by extra
56 * data in order to describe some particular C types.
57 *
58 * type_id:
59 * ~~~~~~~
60 * Each btf_type object is identified by a type_id. The type_id
61 * is implicitly implied by the location of the btf_type object in
62 * the BTF type section. The first one has type_id 1. The second
63 * one has type_id 2...etc. Hence, an earlier btf_type has
64 * a smaller type_id.
65 *
66 * A btf_type object may refer to another btf_type object by using
67 * type_id (i.e. the "type" in the "struct btf_type").
68 *
69 * NOTE that we cannot assume any reference-order.
70 * A btf_type object can refer to an earlier btf_type object
71 * but it can also refer to a later btf_type object.
72 *
73 * For example, to describe "const void *". A btf_type
74 * object describing "const" may refer to another btf_type
75 * object describing "void *". This type-reference is done
76 * by specifying type_id:
77 *
78 * [1] CONST (anon) type_id=2
79 * [2] PTR (anon) type_id=0
80 *
81 * The above is the btf_verifier debug log:
82 * - Each line started with "[?]" is a btf_type object
83 * - [?] is the type_id of the btf_type object.
84 * - CONST/PTR is the BTF_KIND_XXX
85 * - "(anon)" is the name of the type. It just
86 * happens that CONST and PTR has no name.
87 * - type_id=XXX is the 'u32 type' in btf_type
88 *
89 * NOTE: "void" has type_id 0
90 *
91 * String section:
92 * ~~~~~~~~~~~~~~
93 * The BTF string section contains the names used by the type section.
94 * Each string is referred by an "offset" from the beginning of the
95 * string section.
96 *
97 * Each string is '\0' terminated.
98 *
99 * The first character in the string section must be '\0'
100 * which is used to mean 'anonymous'. Some btf_type may not
101 * have a name.
102 */
103
104/* BTF verification:
105 *
106 * To verify BTF data, two passes are needed.
107 *
108 * Pass #1
109 * ~~~~~~~
110 * The first pass is to collect all btf_type objects to
111 * an array: "btf->types".
112 *
113 * Depending on the C type that a btf_type is describing,
114 * a btf_type may be followed by extra data. We don't know
115 * how many btf_type is there, and more importantly we don't
116 * know where each btf_type is located in the type section.
117 *
118 * Without knowing the location of each type_id, most verifications
119 * cannot be done. e.g. an earlier btf_type may refer to a later
120 * btf_type (recall the "const void *" above), so we cannot
121 * check this type-reference in the first pass.
122 *
123 * In the first pass, it still does some verifications (e.g.
124 * checking the name is a valid offset to the string section).
125 *
126 * Pass #2
127 * ~~~~~~~
128 * The main focus is to resolve a btf_type that is referring
129 * to another type.
130 *
131 * We have to ensure the referring type:
132 * 1) does exist in the BTF (i.e. in btf->types[])
133 * 2) does not cause a loop:
134 * struct A {
135 * struct B b;
136 * };
137 *
138 * struct B {
139 * struct A a;
140 * };
141 *
142 * btf_type_needs_resolve() decides if a btf_type needs
143 * to be resolved.
144 *
145 * The needs_resolve type implements the "resolve()" ops which
146 * essentially does a DFS and detects backedge.
147 *
148 * During resolve (or DFS), different C types have different
149 * "RESOLVED" conditions.
150 *
151 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
152 * members because a member is always referring to another
153 * type. A struct's member can be treated as "RESOLVED" if
154 * it is referring to a BTF_KIND_PTR. Otherwise, the
155 * following valid C struct would be rejected:
156 *
157 * struct A {
158 * int m;
159 * struct A *a;
160 * };
161 *
162 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
163 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
164 * detect a pointer loop, e.g.:
165 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
166 * ^ |
167 * +-----------------------------------------+
168 *
169 */
170
171#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
172#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
173#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
174#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
175#define BITS_ROUNDUP_BYTES(bits) \
176 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
177
178#define BTF_INFO_MASK 0x9f00ffff
179#define BTF_INT_MASK 0x0fffffff
180#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
181#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
182
183/* 16MB for 64k structs and each has 16 members and
184 * a few MB spaces for the string section.
185 * The hard limit is S32_MAX.
186 */
187#define BTF_MAX_SIZE (16 * 1024 * 1024)
188
189#define for_each_member_from(i, from, struct_type, member) \
190 for (i = from, member = btf_type_member(struct_type) + from; \
191 i < btf_type_vlen(struct_type); \
192 i++, member++)
193
194#define for_each_vsi_from(i, from, struct_type, member) \
195 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
196 i < btf_type_vlen(struct_type); \
197 i++, member++)
198
199DEFINE_IDR(btf_idr);
200DEFINE_SPINLOCK(btf_idr_lock);
201
202enum btf_kfunc_hook {
203 BTF_KFUNC_HOOK_COMMON,
204 BTF_KFUNC_HOOK_XDP,
205 BTF_KFUNC_HOOK_TC,
206 BTF_KFUNC_HOOK_STRUCT_OPS,
207 BTF_KFUNC_HOOK_TRACING,
208 BTF_KFUNC_HOOK_SYSCALL,
209 BTF_KFUNC_HOOK_FMODRET,
210 BTF_KFUNC_HOOK_MAX,
211};
212
213enum {
214 BTF_KFUNC_SET_MAX_CNT = 256,
215 BTF_DTOR_KFUNC_MAX_CNT = 256,
216};
217
218struct btf_kfunc_set_tab {
219 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
220};
221
222struct btf_id_dtor_kfunc_tab {
223 u32 cnt;
224 struct btf_id_dtor_kfunc dtors[];
225};
226
227struct btf {
228 void *data;
229 struct btf_type **types;
230 u32 *resolved_ids;
231 u32 *resolved_sizes;
232 const char *strings;
233 void *nohdr_data;
234 struct btf_header hdr;
235 u32 nr_types; /* includes VOID for base BTF */
236 u32 types_size;
237 u32 data_size;
238 refcount_t refcnt;
239 u32 id;
240 struct rcu_head rcu;
241 struct btf_kfunc_set_tab *kfunc_set_tab;
242 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
243 struct btf_struct_metas *struct_meta_tab;
244
245 /* split BTF support */
246 struct btf *base_btf;
247 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
248 u32 start_str_off; /* first string offset (0 for base BTF) */
249 char name[MODULE_NAME_LEN];
250 bool kernel_btf;
251};
252
253enum verifier_phase {
254 CHECK_META,
255 CHECK_TYPE,
256};
257
258struct resolve_vertex {
259 const struct btf_type *t;
260 u32 type_id;
261 u16 next_member;
262};
263
264enum visit_state {
265 NOT_VISITED,
266 VISITED,
267 RESOLVED,
268};
269
270enum resolve_mode {
271 RESOLVE_TBD, /* To Be Determined */
272 RESOLVE_PTR, /* Resolving for Pointer */
273 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
274 * or array
275 */
276};
277
278#define MAX_RESOLVE_DEPTH 32
279
280struct btf_sec_info {
281 u32 off;
282 u32 len;
283};
284
285struct btf_verifier_env {
286 struct btf *btf;
287 u8 *visit_states;
288 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
289 struct bpf_verifier_log log;
290 u32 log_type_id;
291 u32 top_stack;
292 enum verifier_phase phase;
293 enum resolve_mode resolve_mode;
294};
295
296static const char * const btf_kind_str[NR_BTF_KINDS] = {
297 [BTF_KIND_UNKN] = "UNKNOWN",
298 [BTF_KIND_INT] = "INT",
299 [BTF_KIND_PTR] = "PTR",
300 [BTF_KIND_ARRAY] = "ARRAY",
301 [BTF_KIND_STRUCT] = "STRUCT",
302 [BTF_KIND_UNION] = "UNION",
303 [BTF_KIND_ENUM] = "ENUM",
304 [BTF_KIND_FWD] = "FWD",
305 [BTF_KIND_TYPEDEF] = "TYPEDEF",
306 [BTF_KIND_VOLATILE] = "VOLATILE",
307 [BTF_KIND_CONST] = "CONST",
308 [BTF_KIND_RESTRICT] = "RESTRICT",
309 [BTF_KIND_FUNC] = "FUNC",
310 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
311 [BTF_KIND_VAR] = "VAR",
312 [BTF_KIND_DATASEC] = "DATASEC",
313 [BTF_KIND_FLOAT] = "FLOAT",
314 [BTF_KIND_DECL_TAG] = "DECL_TAG",
315 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
316 [BTF_KIND_ENUM64] = "ENUM64",
317};
318
319const char *btf_type_str(const struct btf_type *t)
320{
321 return btf_kind_str[BTF_INFO_KIND(t->info)];
322}
323
324/* Chunk size we use in safe copy of data to be shown. */
325#define BTF_SHOW_OBJ_SAFE_SIZE 32
326
327/*
328 * This is the maximum size of a base type value (equivalent to a
329 * 128-bit int); if we are at the end of our safe buffer and have
330 * less than 16 bytes space we can't be assured of being able
331 * to copy the next type safely, so in such cases we will initiate
332 * a new copy.
333 */
334#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
335
336/* Type name size */
337#define BTF_SHOW_NAME_SIZE 80
338
339/*
340 * Common data to all BTF show operations. Private show functions can add
341 * their own data to a structure containing a struct btf_show and consult it
342 * in the show callback. See btf_type_show() below.
343 *
344 * One challenge with showing nested data is we want to skip 0-valued
345 * data, but in order to figure out whether a nested object is all zeros
346 * we need to walk through it. As a result, we need to make two passes
347 * when handling structs, unions and arrays; the first path simply looks
348 * for nonzero data, while the second actually does the display. The first
349 * pass is signalled by show->state.depth_check being set, and if we
350 * encounter a non-zero value we set show->state.depth_to_show to
351 * the depth at which we encountered it. When we have completed the
352 * first pass, we will know if anything needs to be displayed if
353 * depth_to_show > depth. See btf_[struct,array]_show() for the
354 * implementation of this.
355 *
356 * Another problem is we want to ensure the data for display is safe to
357 * access. To support this, the anonymous "struct {} obj" tracks the data
358 * object and our safe copy of it. We copy portions of the data needed
359 * to the object "copy" buffer, but because its size is limited to
360 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
361 * traverse larger objects for display.
362 *
363 * The various data type show functions all start with a call to
364 * btf_show_start_type() which returns a pointer to the safe copy
365 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
366 * raw data itself). btf_show_obj_safe() is responsible for
367 * using copy_from_kernel_nofault() to update the safe data if necessary
368 * as we traverse the object's data. skbuff-like semantics are
369 * used:
370 *
371 * - obj.head points to the start of the toplevel object for display
372 * - obj.size is the size of the toplevel object
373 * - obj.data points to the current point in the original data at
374 * which our safe data starts. obj.data will advance as we copy
375 * portions of the data.
376 *
377 * In most cases a single copy will suffice, but larger data structures
378 * such as "struct task_struct" will require many copies. The logic in
379 * btf_show_obj_safe() handles the logic that determines if a new
380 * copy_from_kernel_nofault() is needed.
381 */
382struct btf_show {
383 u64 flags;
384 void *target; /* target of show operation (seq file, buffer) */
385 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
386 const struct btf *btf;
387 /* below are used during iteration */
388 struct {
389 u8 depth;
390 u8 depth_to_show;
391 u8 depth_check;
392 u8 array_member:1,
393 array_terminated:1;
394 u16 array_encoding;
395 u32 type_id;
396 int status; /* non-zero for error */
397 const struct btf_type *type;
398 const struct btf_member *member;
399 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
400 } state;
401 struct {
402 u32 size;
403 void *head;
404 void *data;
405 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
406 } obj;
407};
408
409struct btf_kind_operations {
410 s32 (*check_meta)(struct btf_verifier_env *env,
411 const struct btf_type *t,
412 u32 meta_left);
413 int (*resolve)(struct btf_verifier_env *env,
414 const struct resolve_vertex *v);
415 int (*check_member)(struct btf_verifier_env *env,
416 const struct btf_type *struct_type,
417 const struct btf_member *member,
418 const struct btf_type *member_type);
419 int (*check_kflag_member)(struct btf_verifier_env *env,
420 const struct btf_type *struct_type,
421 const struct btf_member *member,
422 const struct btf_type *member_type);
423 void (*log_details)(struct btf_verifier_env *env,
424 const struct btf_type *t);
425 void (*show)(const struct btf *btf, const struct btf_type *t,
426 u32 type_id, void *data, u8 bits_offsets,
427 struct btf_show *show);
428};
429
430static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
431static struct btf_type btf_void;
432
433static int btf_resolve(struct btf_verifier_env *env,
434 const struct btf_type *t, u32 type_id);
435
436static int btf_func_check(struct btf_verifier_env *env,
437 const struct btf_type *t);
438
439static bool btf_type_is_modifier(const struct btf_type *t)
440{
441 /* Some of them is not strictly a C modifier
442 * but they are grouped into the same bucket
443 * for BTF concern:
444 * A type (t) that refers to another
445 * type through t->type AND its size cannot
446 * be determined without following the t->type.
447 *
448 * ptr does not fall into this bucket
449 * because its size is always sizeof(void *).
450 */
451 switch (BTF_INFO_KIND(t->info)) {
452 case BTF_KIND_TYPEDEF:
453 case BTF_KIND_VOLATILE:
454 case BTF_KIND_CONST:
455 case BTF_KIND_RESTRICT:
456 case BTF_KIND_TYPE_TAG:
457 return true;
458 }
459
460 return false;
461}
462
463bool btf_type_is_void(const struct btf_type *t)
464{
465 return t == &btf_void;
466}
467
468static bool btf_type_is_fwd(const struct btf_type *t)
469{
470 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
471}
472
473static bool btf_type_nosize(const struct btf_type *t)
474{
475 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
476 btf_type_is_func(t) || btf_type_is_func_proto(t);
477}
478
479static bool btf_type_nosize_or_null(const struct btf_type *t)
480{
481 return !t || btf_type_nosize(t);
482}
483
484static bool btf_type_is_datasec(const struct btf_type *t)
485{
486 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
487}
488
489static bool btf_type_is_decl_tag(const struct btf_type *t)
490{
491 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
492}
493
494static bool btf_type_is_decl_tag_target(const struct btf_type *t)
495{
496 return btf_type_is_func(t) || btf_type_is_struct(t) ||
497 btf_type_is_var(t) || btf_type_is_typedef(t);
498}
499
500u32 btf_nr_types(const struct btf *btf)
501{
502 u32 total = 0;
503
504 while (btf) {
505 total += btf->nr_types;
506 btf = btf->base_btf;
507 }
508
509 return total;
510}
511
512s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
513{
514 const struct btf_type *t;
515 const char *tname;
516 u32 i, total;
517
518 total = btf_nr_types(btf);
519 for (i = 1; i < total; i++) {
520 t = btf_type_by_id(btf, i);
521 if (BTF_INFO_KIND(t->info) != kind)
522 continue;
523
524 tname = btf_name_by_offset(btf, t->name_off);
525 if (!strcmp(tname, name))
526 return i;
527 }
528
529 return -ENOENT;
530}
531
532static s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
533{
534 struct btf *btf;
535 s32 ret;
536 int id;
537
538 btf = bpf_get_btf_vmlinux();
539 if (IS_ERR(btf))
540 return PTR_ERR(btf);
541 if (!btf)
542 return -EINVAL;
543
544 ret = btf_find_by_name_kind(btf, name, kind);
545 /* ret is never zero, since btf_find_by_name_kind returns
546 * positive btf_id or negative error.
547 */
548 if (ret > 0) {
549 btf_get(btf);
550 *btf_p = btf;
551 return ret;
552 }
553
554 /* If name is not found in vmlinux's BTF then search in module's BTFs */
555 spin_lock_bh(&btf_idr_lock);
556 idr_for_each_entry(&btf_idr, btf, id) {
557 if (!btf_is_module(btf))
558 continue;
559 /* linear search could be slow hence unlock/lock
560 * the IDR to avoiding holding it for too long
561 */
562 btf_get(btf);
563 spin_unlock_bh(&btf_idr_lock);
564 ret = btf_find_by_name_kind(btf, name, kind);
565 if (ret > 0) {
566 *btf_p = btf;
567 return ret;
568 }
569 spin_lock_bh(&btf_idr_lock);
570 btf_put(btf);
571 }
572 spin_unlock_bh(&btf_idr_lock);
573 return ret;
574}
575
576const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
577 u32 id, u32 *res_id)
578{
579 const struct btf_type *t = btf_type_by_id(btf, id);
580
581 while (btf_type_is_modifier(t)) {
582 id = t->type;
583 t = btf_type_by_id(btf, t->type);
584 }
585
586 if (res_id)
587 *res_id = id;
588
589 return t;
590}
591
592const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
593 u32 id, u32 *res_id)
594{
595 const struct btf_type *t;
596
597 t = btf_type_skip_modifiers(btf, id, NULL);
598 if (!btf_type_is_ptr(t))
599 return NULL;
600
601 return btf_type_skip_modifiers(btf, t->type, res_id);
602}
603
604const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
605 u32 id, u32 *res_id)
606{
607 const struct btf_type *ptype;
608
609 ptype = btf_type_resolve_ptr(btf, id, res_id);
610 if (ptype && btf_type_is_func_proto(ptype))
611 return ptype;
612
613 return NULL;
614}
615
616/* Types that act only as a source, not sink or intermediate
617 * type when resolving.
618 */
619static bool btf_type_is_resolve_source_only(const struct btf_type *t)
620{
621 return btf_type_is_var(t) ||
622 btf_type_is_decl_tag(t) ||
623 btf_type_is_datasec(t);
624}
625
626/* What types need to be resolved?
627 *
628 * btf_type_is_modifier() is an obvious one.
629 *
630 * btf_type_is_struct() because its member refers to
631 * another type (through member->type).
632 *
633 * btf_type_is_var() because the variable refers to
634 * another type. btf_type_is_datasec() holds multiple
635 * btf_type_is_var() types that need resolving.
636 *
637 * btf_type_is_array() because its element (array->type)
638 * refers to another type. Array can be thought of a
639 * special case of struct while array just has the same
640 * member-type repeated by array->nelems of times.
641 */
642static bool btf_type_needs_resolve(const struct btf_type *t)
643{
644 return btf_type_is_modifier(t) ||
645 btf_type_is_ptr(t) ||
646 btf_type_is_struct(t) ||
647 btf_type_is_array(t) ||
648 btf_type_is_var(t) ||
649 btf_type_is_func(t) ||
650 btf_type_is_decl_tag(t) ||
651 btf_type_is_datasec(t);
652}
653
654/* t->size can be used */
655static bool btf_type_has_size(const struct btf_type *t)
656{
657 switch (BTF_INFO_KIND(t->info)) {
658 case BTF_KIND_INT:
659 case BTF_KIND_STRUCT:
660 case BTF_KIND_UNION:
661 case BTF_KIND_ENUM:
662 case BTF_KIND_DATASEC:
663 case BTF_KIND_FLOAT:
664 case BTF_KIND_ENUM64:
665 return true;
666 }
667
668 return false;
669}
670
671static const char *btf_int_encoding_str(u8 encoding)
672{
673 if (encoding == 0)
674 return "(none)";
675 else if (encoding == BTF_INT_SIGNED)
676 return "SIGNED";
677 else if (encoding == BTF_INT_CHAR)
678 return "CHAR";
679 else if (encoding == BTF_INT_BOOL)
680 return "BOOL";
681 else
682 return "UNKN";
683}
684
685static u32 btf_type_int(const struct btf_type *t)
686{
687 return *(u32 *)(t + 1);
688}
689
690static const struct btf_array *btf_type_array(const struct btf_type *t)
691{
692 return (const struct btf_array *)(t + 1);
693}
694
695static const struct btf_enum *btf_type_enum(const struct btf_type *t)
696{
697 return (const struct btf_enum *)(t + 1);
698}
699
700static const struct btf_var *btf_type_var(const struct btf_type *t)
701{
702 return (const struct btf_var *)(t + 1);
703}
704
705static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
706{
707 return (const struct btf_decl_tag *)(t + 1);
708}
709
710static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
711{
712 return (const struct btf_enum64 *)(t + 1);
713}
714
715static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
716{
717 return kind_ops[BTF_INFO_KIND(t->info)];
718}
719
720static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
721{
722 if (!BTF_STR_OFFSET_VALID(offset))
723 return false;
724
725 while (offset < btf->start_str_off)
726 btf = btf->base_btf;
727
728 offset -= btf->start_str_off;
729 return offset < btf->hdr.str_len;
730}
731
732static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
733{
734 if ((first ? !isalpha(c) :
735 !isalnum(c)) &&
736 c != '_' &&
737 ((c == '.' && !dot_ok) ||
738 c != '.'))
739 return false;
740 return true;
741}
742
743static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
744{
745 while (offset < btf->start_str_off)
746 btf = btf->base_btf;
747
748 offset -= btf->start_str_off;
749 if (offset < btf->hdr.str_len)
750 return &btf->strings[offset];
751
752 return NULL;
753}
754
755static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
756{
757 /* offset must be valid */
758 const char *src = btf_str_by_offset(btf, offset);
759 const char *src_limit;
760
761 if (!__btf_name_char_ok(*src, true, dot_ok))
762 return false;
763
764 /* set a limit on identifier length */
765 src_limit = src + KSYM_NAME_LEN;
766 src++;
767 while (*src && src < src_limit) {
768 if (!__btf_name_char_ok(*src, false, dot_ok))
769 return false;
770 src++;
771 }
772
773 return !*src;
774}
775
776/* Only C-style identifier is permitted. This can be relaxed if
777 * necessary.
778 */
779static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
780{
781 return __btf_name_valid(btf, offset, false);
782}
783
784static bool btf_name_valid_section(const struct btf *btf, u32 offset)
785{
786 return __btf_name_valid(btf, offset, true);
787}
788
789static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
790{
791 const char *name;
792
793 if (!offset)
794 return "(anon)";
795
796 name = btf_str_by_offset(btf, offset);
797 return name ?: "(invalid-name-offset)";
798}
799
800const char *btf_name_by_offset(const struct btf *btf, u32 offset)
801{
802 return btf_str_by_offset(btf, offset);
803}
804
805const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
806{
807 while (type_id < btf->start_id)
808 btf = btf->base_btf;
809
810 type_id -= btf->start_id;
811 if (type_id >= btf->nr_types)
812 return NULL;
813 return btf->types[type_id];
814}
815EXPORT_SYMBOL_GPL(btf_type_by_id);
816
817/*
818 * Regular int is not a bit field and it must be either
819 * u8/u16/u32/u64 or __int128.
820 */
821static bool btf_type_int_is_regular(const struct btf_type *t)
822{
823 u8 nr_bits, nr_bytes;
824 u32 int_data;
825
826 int_data = btf_type_int(t);
827 nr_bits = BTF_INT_BITS(int_data);
828 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
829 if (BITS_PER_BYTE_MASKED(nr_bits) ||
830 BTF_INT_OFFSET(int_data) ||
831 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
832 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
833 nr_bytes != (2 * sizeof(u64)))) {
834 return false;
835 }
836
837 return true;
838}
839
840/*
841 * Check that given struct member is a regular int with expected
842 * offset and size.
843 */
844bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
845 const struct btf_member *m,
846 u32 expected_offset, u32 expected_size)
847{
848 const struct btf_type *t;
849 u32 id, int_data;
850 u8 nr_bits;
851
852 id = m->type;
853 t = btf_type_id_size(btf, &id, NULL);
854 if (!t || !btf_type_is_int(t))
855 return false;
856
857 int_data = btf_type_int(t);
858 nr_bits = BTF_INT_BITS(int_data);
859 if (btf_type_kflag(s)) {
860 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
861 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
862
863 /* if kflag set, int should be a regular int and
864 * bit offset should be at byte boundary.
865 */
866 return !bitfield_size &&
867 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
868 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
869 }
870
871 if (BTF_INT_OFFSET(int_data) ||
872 BITS_PER_BYTE_MASKED(m->offset) ||
873 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
874 BITS_PER_BYTE_MASKED(nr_bits) ||
875 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
876 return false;
877
878 return true;
879}
880
881/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
882static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
883 u32 id)
884{
885 const struct btf_type *t = btf_type_by_id(btf, id);
886
887 while (btf_type_is_modifier(t) &&
888 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
889 t = btf_type_by_id(btf, t->type);
890 }
891
892 return t;
893}
894
895#define BTF_SHOW_MAX_ITER 10
896
897#define BTF_KIND_BIT(kind) (1ULL << kind)
898
899/*
900 * Populate show->state.name with type name information.
901 * Format of type name is
902 *
903 * [.member_name = ] (type_name)
904 */
905static const char *btf_show_name(struct btf_show *show)
906{
907 /* BTF_MAX_ITER array suffixes "[]" */
908 const char *array_suffixes = "[][][][][][][][][][]";
909 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
910 /* BTF_MAX_ITER pointer suffixes "*" */
911 const char *ptr_suffixes = "**********";
912 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
913 const char *name = NULL, *prefix = "", *parens = "";
914 const struct btf_member *m = show->state.member;
915 const struct btf_type *t;
916 const struct btf_array *array;
917 u32 id = show->state.type_id;
918 const char *member = NULL;
919 bool show_member = false;
920 u64 kinds = 0;
921 int i;
922
923 show->state.name[0] = '\0';
924
925 /*
926 * Don't show type name if we're showing an array member;
927 * in that case we show the array type so don't need to repeat
928 * ourselves for each member.
929 */
930 if (show->state.array_member)
931 return "";
932
933 /* Retrieve member name, if any. */
934 if (m) {
935 member = btf_name_by_offset(show->btf, m->name_off);
936 show_member = strlen(member) > 0;
937 id = m->type;
938 }
939
940 /*
941 * Start with type_id, as we have resolved the struct btf_type *
942 * via btf_modifier_show() past the parent typedef to the child
943 * struct, int etc it is defined as. In such cases, the type_id
944 * still represents the starting type while the struct btf_type *
945 * in our show->state points at the resolved type of the typedef.
946 */
947 t = btf_type_by_id(show->btf, id);
948 if (!t)
949 return "";
950
951 /*
952 * The goal here is to build up the right number of pointer and
953 * array suffixes while ensuring the type name for a typedef
954 * is represented. Along the way we accumulate a list of
955 * BTF kinds we have encountered, since these will inform later
956 * display; for example, pointer types will not require an
957 * opening "{" for struct, we will just display the pointer value.
958 *
959 * We also want to accumulate the right number of pointer or array
960 * indices in the format string while iterating until we get to
961 * the typedef/pointee/array member target type.
962 *
963 * We start by pointing at the end of pointer and array suffix
964 * strings; as we accumulate pointers and arrays we move the pointer
965 * or array string backwards so it will show the expected number of
966 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
967 * and/or arrays and typedefs are supported as a precaution.
968 *
969 * We also want to get typedef name while proceeding to resolve
970 * type it points to so that we can add parentheses if it is a
971 * "typedef struct" etc.
972 */
973 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
974
975 switch (BTF_INFO_KIND(t->info)) {
976 case BTF_KIND_TYPEDEF:
977 if (!name)
978 name = btf_name_by_offset(show->btf,
979 t->name_off);
980 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
981 id = t->type;
982 break;
983 case BTF_KIND_ARRAY:
984 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
985 parens = "[";
986 if (!t)
987 return "";
988 array = btf_type_array(t);
989 if (array_suffix > array_suffixes)
990 array_suffix -= 2;
991 id = array->type;
992 break;
993 case BTF_KIND_PTR:
994 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
995 if (ptr_suffix > ptr_suffixes)
996 ptr_suffix -= 1;
997 id = t->type;
998 break;
999 default:
1000 id = 0;
1001 break;
1002 }
1003 if (!id)
1004 break;
1005 t = btf_type_skip_qualifiers(show->btf, id);
1006 }
1007 /* We may not be able to represent this type; bail to be safe */
1008 if (i == BTF_SHOW_MAX_ITER)
1009 return "";
1010
1011 if (!name)
1012 name = btf_name_by_offset(show->btf, t->name_off);
1013
1014 switch (BTF_INFO_KIND(t->info)) {
1015 case BTF_KIND_STRUCT:
1016 case BTF_KIND_UNION:
1017 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1018 "struct" : "union";
1019 /* if it's an array of struct/union, parens is already set */
1020 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1021 parens = "{";
1022 break;
1023 case BTF_KIND_ENUM:
1024 case BTF_KIND_ENUM64:
1025 prefix = "enum";
1026 break;
1027 default:
1028 break;
1029 }
1030
1031 /* pointer does not require parens */
1032 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1033 parens = "";
1034 /* typedef does not require struct/union/enum prefix */
1035 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1036 prefix = "";
1037
1038 if (!name)
1039 name = "";
1040
1041 /* Even if we don't want type name info, we want parentheses etc */
1042 if (show->flags & BTF_SHOW_NONAME)
1043 snprintf(show->state.name, sizeof(show->state.name), "%s",
1044 parens);
1045 else
1046 snprintf(show->state.name, sizeof(show->state.name),
1047 "%s%s%s(%s%s%s%s%s%s)%s",
1048 /* first 3 strings comprise ".member = " */
1049 show_member ? "." : "",
1050 show_member ? member : "",
1051 show_member ? " = " : "",
1052 /* ...next is our prefix (struct, enum, etc) */
1053 prefix,
1054 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1055 /* ...this is the type name itself */
1056 name,
1057 /* ...suffixed by the appropriate '*', '[]' suffixes */
1058 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1059 array_suffix, parens);
1060
1061 return show->state.name;
1062}
1063
1064static const char *__btf_show_indent(struct btf_show *show)
1065{
1066 const char *indents = " ";
1067 const char *indent = &indents[strlen(indents)];
1068
1069 if ((indent - show->state.depth) >= indents)
1070 return indent - show->state.depth;
1071 return indents;
1072}
1073
1074static const char *btf_show_indent(struct btf_show *show)
1075{
1076 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1077}
1078
1079static const char *btf_show_newline(struct btf_show *show)
1080{
1081 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1082}
1083
1084static const char *btf_show_delim(struct btf_show *show)
1085{
1086 if (show->state.depth == 0)
1087 return "";
1088
1089 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1090 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1091 return "|";
1092
1093 return ",";
1094}
1095
1096__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1097{
1098 va_list args;
1099
1100 if (!show->state.depth_check) {
1101 va_start(args, fmt);
1102 show->showfn(show, fmt, args);
1103 va_end(args);
1104 }
1105}
1106
1107/* Macros are used here as btf_show_type_value[s]() prepends and appends
1108 * format specifiers to the format specifier passed in; these do the work of
1109 * adding indentation, delimiters etc while the caller simply has to specify
1110 * the type value(s) in the format specifier + value(s).
1111 */
1112#define btf_show_type_value(show, fmt, value) \
1113 do { \
1114 if ((value) != (__typeof__(value))0 || \
1115 (show->flags & BTF_SHOW_ZERO) || \
1116 show->state.depth == 0) { \
1117 btf_show(show, "%s%s" fmt "%s%s", \
1118 btf_show_indent(show), \
1119 btf_show_name(show), \
1120 value, btf_show_delim(show), \
1121 btf_show_newline(show)); \
1122 if (show->state.depth > show->state.depth_to_show) \
1123 show->state.depth_to_show = show->state.depth; \
1124 } \
1125 } while (0)
1126
1127#define btf_show_type_values(show, fmt, ...) \
1128 do { \
1129 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1130 btf_show_name(show), \
1131 __VA_ARGS__, btf_show_delim(show), \
1132 btf_show_newline(show)); \
1133 if (show->state.depth > show->state.depth_to_show) \
1134 show->state.depth_to_show = show->state.depth; \
1135 } while (0)
1136
1137/* How much is left to copy to safe buffer after @data? */
1138static int btf_show_obj_size_left(struct btf_show *show, void *data)
1139{
1140 return show->obj.head + show->obj.size - data;
1141}
1142
1143/* Is object pointed to by @data of @size already copied to our safe buffer? */
1144static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1145{
1146 return data >= show->obj.data &&
1147 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1148}
1149
1150/*
1151 * If object pointed to by @data of @size falls within our safe buffer, return
1152 * the equivalent pointer to the same safe data. Assumes
1153 * copy_from_kernel_nofault() has already happened and our safe buffer is
1154 * populated.
1155 */
1156static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1157{
1158 if (btf_show_obj_is_safe(show, data, size))
1159 return show->obj.safe + (data - show->obj.data);
1160 return NULL;
1161}
1162
1163/*
1164 * Return a safe-to-access version of data pointed to by @data.
1165 * We do this by copying the relevant amount of information
1166 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1167 *
1168 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1169 * safe copy is needed.
1170 *
1171 * Otherwise we need to determine if we have the required amount
1172 * of data (determined by the @data pointer and the size of the
1173 * largest base type we can encounter (represented by
1174 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1175 * that we will be able to print some of the current object,
1176 * and if more is needed a copy will be triggered.
1177 * Some objects such as structs will not fit into the buffer;
1178 * in such cases additional copies when we iterate over their
1179 * members may be needed.
1180 *
1181 * btf_show_obj_safe() is used to return a safe buffer for
1182 * btf_show_start_type(); this ensures that as we recurse into
1183 * nested types we always have safe data for the given type.
1184 * This approach is somewhat wasteful; it's possible for example
1185 * that when iterating over a large union we'll end up copying the
1186 * same data repeatedly, but the goal is safety not performance.
1187 * We use stack data as opposed to per-CPU buffers because the
1188 * iteration over a type can take some time, and preemption handling
1189 * would greatly complicate use of the safe buffer.
1190 */
1191static void *btf_show_obj_safe(struct btf_show *show,
1192 const struct btf_type *t,
1193 void *data)
1194{
1195 const struct btf_type *rt;
1196 int size_left, size;
1197 void *safe = NULL;
1198
1199 if (show->flags & BTF_SHOW_UNSAFE)
1200 return data;
1201
1202 rt = btf_resolve_size(show->btf, t, &size);
1203 if (IS_ERR(rt)) {
1204 show->state.status = PTR_ERR(rt);
1205 return NULL;
1206 }
1207
1208 /*
1209 * Is this toplevel object? If so, set total object size and
1210 * initialize pointers. Otherwise check if we still fall within
1211 * our safe object data.
1212 */
1213 if (show->state.depth == 0) {
1214 show->obj.size = size;
1215 show->obj.head = data;
1216 } else {
1217 /*
1218 * If the size of the current object is > our remaining
1219 * safe buffer we _may_ need to do a new copy. However
1220 * consider the case of a nested struct; it's size pushes
1221 * us over the safe buffer limit, but showing any individual
1222 * struct members does not. In such cases, we don't need
1223 * to initiate a fresh copy yet; however we definitely need
1224 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1225 * in our buffer, regardless of the current object size.
1226 * The logic here is that as we resolve types we will
1227 * hit a base type at some point, and we need to be sure
1228 * the next chunk of data is safely available to display
1229 * that type info safely. We cannot rely on the size of
1230 * the current object here because it may be much larger
1231 * than our current buffer (e.g. task_struct is 8k).
1232 * All we want to do here is ensure that we can print the
1233 * next basic type, which we can if either
1234 * - the current type size is within the safe buffer; or
1235 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1236 * the safe buffer.
1237 */
1238 safe = __btf_show_obj_safe(show, data,
1239 min(size,
1240 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1241 }
1242
1243 /*
1244 * We need a new copy to our safe object, either because we haven't
1245 * yet copied and are initializing safe data, or because the data
1246 * we want falls outside the boundaries of the safe object.
1247 */
1248 if (!safe) {
1249 size_left = btf_show_obj_size_left(show, data);
1250 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1251 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1252 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1253 data, size_left);
1254 if (!show->state.status) {
1255 show->obj.data = data;
1256 safe = show->obj.safe;
1257 }
1258 }
1259
1260 return safe;
1261}
1262
1263/*
1264 * Set the type we are starting to show and return a safe data pointer
1265 * to be used for showing the associated data.
1266 */
1267static void *btf_show_start_type(struct btf_show *show,
1268 const struct btf_type *t,
1269 u32 type_id, void *data)
1270{
1271 show->state.type = t;
1272 show->state.type_id = type_id;
1273 show->state.name[0] = '\0';
1274
1275 return btf_show_obj_safe(show, t, data);
1276}
1277
1278static void btf_show_end_type(struct btf_show *show)
1279{
1280 show->state.type = NULL;
1281 show->state.type_id = 0;
1282 show->state.name[0] = '\0';
1283}
1284
1285static void *btf_show_start_aggr_type(struct btf_show *show,
1286 const struct btf_type *t,
1287 u32 type_id, void *data)
1288{
1289 void *safe_data = btf_show_start_type(show, t, type_id, data);
1290
1291 if (!safe_data)
1292 return safe_data;
1293
1294 btf_show(show, "%s%s%s", btf_show_indent(show),
1295 btf_show_name(show),
1296 btf_show_newline(show));
1297 show->state.depth++;
1298 return safe_data;
1299}
1300
1301static void btf_show_end_aggr_type(struct btf_show *show,
1302 const char *suffix)
1303{
1304 show->state.depth--;
1305 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1306 btf_show_delim(show), btf_show_newline(show));
1307 btf_show_end_type(show);
1308}
1309
1310static void btf_show_start_member(struct btf_show *show,
1311 const struct btf_member *m)
1312{
1313 show->state.member = m;
1314}
1315
1316static void btf_show_start_array_member(struct btf_show *show)
1317{
1318 show->state.array_member = 1;
1319 btf_show_start_member(show, NULL);
1320}
1321
1322static void btf_show_end_member(struct btf_show *show)
1323{
1324 show->state.member = NULL;
1325}
1326
1327static void btf_show_end_array_member(struct btf_show *show)
1328{
1329 show->state.array_member = 0;
1330 btf_show_end_member(show);
1331}
1332
1333static void *btf_show_start_array_type(struct btf_show *show,
1334 const struct btf_type *t,
1335 u32 type_id,
1336 u16 array_encoding,
1337 void *data)
1338{
1339 show->state.array_encoding = array_encoding;
1340 show->state.array_terminated = 0;
1341 return btf_show_start_aggr_type(show, t, type_id, data);
1342}
1343
1344static void btf_show_end_array_type(struct btf_show *show)
1345{
1346 show->state.array_encoding = 0;
1347 show->state.array_terminated = 0;
1348 btf_show_end_aggr_type(show, "]");
1349}
1350
1351static void *btf_show_start_struct_type(struct btf_show *show,
1352 const struct btf_type *t,
1353 u32 type_id,
1354 void *data)
1355{
1356 return btf_show_start_aggr_type(show, t, type_id, data);
1357}
1358
1359static void btf_show_end_struct_type(struct btf_show *show)
1360{
1361 btf_show_end_aggr_type(show, "}");
1362}
1363
1364__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1365 const char *fmt, ...)
1366{
1367 va_list args;
1368
1369 va_start(args, fmt);
1370 bpf_verifier_vlog(log, fmt, args);
1371 va_end(args);
1372}
1373
1374__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1375 const char *fmt, ...)
1376{
1377 struct bpf_verifier_log *log = &env->log;
1378 va_list args;
1379
1380 if (!bpf_verifier_log_needed(log))
1381 return;
1382
1383 va_start(args, fmt);
1384 bpf_verifier_vlog(log, fmt, args);
1385 va_end(args);
1386}
1387
1388__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1389 const struct btf_type *t,
1390 bool log_details,
1391 const char *fmt, ...)
1392{
1393 struct bpf_verifier_log *log = &env->log;
1394 struct btf *btf = env->btf;
1395 va_list args;
1396
1397 if (!bpf_verifier_log_needed(log))
1398 return;
1399
1400 /* btf verifier prints all types it is processing via
1401 * btf_verifier_log_type(..., fmt = NULL).
1402 * Skip those prints for in-kernel BTF verification.
1403 */
1404 if (log->level == BPF_LOG_KERNEL && !fmt)
1405 return;
1406
1407 __btf_verifier_log(log, "[%u] %s %s%s",
1408 env->log_type_id,
1409 btf_type_str(t),
1410 __btf_name_by_offset(btf, t->name_off),
1411 log_details ? " " : "");
1412
1413 if (log_details)
1414 btf_type_ops(t)->log_details(env, t);
1415
1416 if (fmt && *fmt) {
1417 __btf_verifier_log(log, " ");
1418 va_start(args, fmt);
1419 bpf_verifier_vlog(log, fmt, args);
1420 va_end(args);
1421 }
1422
1423 __btf_verifier_log(log, "\n");
1424}
1425
1426#define btf_verifier_log_type(env, t, ...) \
1427 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1428#define btf_verifier_log_basic(env, t, ...) \
1429 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1430
1431__printf(4, 5)
1432static void btf_verifier_log_member(struct btf_verifier_env *env,
1433 const struct btf_type *struct_type,
1434 const struct btf_member *member,
1435 const char *fmt, ...)
1436{
1437 struct bpf_verifier_log *log = &env->log;
1438 struct btf *btf = env->btf;
1439 va_list args;
1440
1441 if (!bpf_verifier_log_needed(log))
1442 return;
1443
1444 if (log->level == BPF_LOG_KERNEL && !fmt)
1445 return;
1446 /* The CHECK_META phase already did a btf dump.
1447 *
1448 * If member is logged again, it must hit an error in
1449 * parsing this member. It is useful to print out which
1450 * struct this member belongs to.
1451 */
1452 if (env->phase != CHECK_META)
1453 btf_verifier_log_type(env, struct_type, NULL);
1454
1455 if (btf_type_kflag(struct_type))
1456 __btf_verifier_log(log,
1457 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1458 __btf_name_by_offset(btf, member->name_off),
1459 member->type,
1460 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1461 BTF_MEMBER_BIT_OFFSET(member->offset));
1462 else
1463 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1464 __btf_name_by_offset(btf, member->name_off),
1465 member->type, member->offset);
1466
1467 if (fmt && *fmt) {
1468 __btf_verifier_log(log, " ");
1469 va_start(args, fmt);
1470 bpf_verifier_vlog(log, fmt, args);
1471 va_end(args);
1472 }
1473
1474 __btf_verifier_log(log, "\n");
1475}
1476
1477__printf(4, 5)
1478static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1479 const struct btf_type *datasec_type,
1480 const struct btf_var_secinfo *vsi,
1481 const char *fmt, ...)
1482{
1483 struct bpf_verifier_log *log = &env->log;
1484 va_list args;
1485
1486 if (!bpf_verifier_log_needed(log))
1487 return;
1488 if (log->level == BPF_LOG_KERNEL && !fmt)
1489 return;
1490 if (env->phase != CHECK_META)
1491 btf_verifier_log_type(env, datasec_type, NULL);
1492
1493 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1494 vsi->type, vsi->offset, vsi->size);
1495 if (fmt && *fmt) {
1496 __btf_verifier_log(log, " ");
1497 va_start(args, fmt);
1498 bpf_verifier_vlog(log, fmt, args);
1499 va_end(args);
1500 }
1501
1502 __btf_verifier_log(log, "\n");
1503}
1504
1505static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1506 u32 btf_data_size)
1507{
1508 struct bpf_verifier_log *log = &env->log;
1509 const struct btf *btf = env->btf;
1510 const struct btf_header *hdr;
1511
1512 if (!bpf_verifier_log_needed(log))
1513 return;
1514
1515 if (log->level == BPF_LOG_KERNEL)
1516 return;
1517 hdr = &btf->hdr;
1518 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1519 __btf_verifier_log(log, "version: %u\n", hdr->version);
1520 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1521 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1522 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1523 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1524 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1525 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1526 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1527}
1528
1529static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1530{
1531 struct btf *btf = env->btf;
1532
1533 if (btf->types_size == btf->nr_types) {
1534 /* Expand 'types' array */
1535
1536 struct btf_type **new_types;
1537 u32 expand_by, new_size;
1538
1539 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1540 btf_verifier_log(env, "Exceeded max num of types");
1541 return -E2BIG;
1542 }
1543
1544 expand_by = max_t(u32, btf->types_size >> 2, 16);
1545 new_size = min_t(u32, BTF_MAX_TYPE,
1546 btf->types_size + expand_by);
1547
1548 new_types = kvcalloc(new_size, sizeof(*new_types),
1549 GFP_KERNEL | __GFP_NOWARN);
1550 if (!new_types)
1551 return -ENOMEM;
1552
1553 if (btf->nr_types == 0) {
1554 if (!btf->base_btf) {
1555 /* lazily init VOID type */
1556 new_types[0] = &btf_void;
1557 btf->nr_types++;
1558 }
1559 } else {
1560 memcpy(new_types, btf->types,
1561 sizeof(*btf->types) * btf->nr_types);
1562 }
1563
1564 kvfree(btf->types);
1565 btf->types = new_types;
1566 btf->types_size = new_size;
1567 }
1568
1569 btf->types[btf->nr_types++] = t;
1570
1571 return 0;
1572}
1573
1574static int btf_alloc_id(struct btf *btf)
1575{
1576 int id;
1577
1578 idr_preload(GFP_KERNEL);
1579 spin_lock_bh(&btf_idr_lock);
1580 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1581 if (id > 0)
1582 btf->id = id;
1583 spin_unlock_bh(&btf_idr_lock);
1584 idr_preload_end();
1585
1586 if (WARN_ON_ONCE(!id))
1587 return -ENOSPC;
1588
1589 return id > 0 ? 0 : id;
1590}
1591
1592static void btf_free_id(struct btf *btf)
1593{
1594 unsigned long flags;
1595
1596 /*
1597 * In map-in-map, calling map_delete_elem() on outer
1598 * map will call bpf_map_put on the inner map.
1599 * It will then eventually call btf_free_id()
1600 * on the inner map. Some of the map_delete_elem()
1601 * implementation may have irq disabled, so
1602 * we need to use the _irqsave() version instead
1603 * of the _bh() version.
1604 */
1605 spin_lock_irqsave(&btf_idr_lock, flags);
1606 idr_remove(&btf_idr, btf->id);
1607 spin_unlock_irqrestore(&btf_idr_lock, flags);
1608}
1609
1610static void btf_free_kfunc_set_tab(struct btf *btf)
1611{
1612 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1613 int hook;
1614
1615 if (!tab)
1616 return;
1617 /* For module BTF, we directly assign the sets being registered, so
1618 * there is nothing to free except kfunc_set_tab.
1619 */
1620 if (btf_is_module(btf))
1621 goto free_tab;
1622 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1623 kfree(tab->sets[hook]);
1624free_tab:
1625 kfree(tab);
1626 btf->kfunc_set_tab = NULL;
1627}
1628
1629static void btf_free_dtor_kfunc_tab(struct btf *btf)
1630{
1631 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1632
1633 if (!tab)
1634 return;
1635 kfree(tab);
1636 btf->dtor_kfunc_tab = NULL;
1637}
1638
1639static void btf_struct_metas_free(struct btf_struct_metas *tab)
1640{
1641 int i;
1642
1643 if (!tab)
1644 return;
1645 for (i = 0; i < tab->cnt; i++) {
1646 btf_record_free(tab->types[i].record);
1647 kfree(tab->types[i].field_offs);
1648 }
1649 kfree(tab);
1650}
1651
1652static void btf_free_struct_meta_tab(struct btf *btf)
1653{
1654 struct btf_struct_metas *tab = btf->struct_meta_tab;
1655
1656 btf_struct_metas_free(tab);
1657 btf->struct_meta_tab = NULL;
1658}
1659
1660static void btf_free(struct btf *btf)
1661{
1662 btf_free_struct_meta_tab(btf);
1663 btf_free_dtor_kfunc_tab(btf);
1664 btf_free_kfunc_set_tab(btf);
1665 kvfree(btf->types);
1666 kvfree(btf->resolved_sizes);
1667 kvfree(btf->resolved_ids);
1668 kvfree(btf->data);
1669 kfree(btf);
1670}
1671
1672static void btf_free_rcu(struct rcu_head *rcu)
1673{
1674 struct btf *btf = container_of(rcu, struct btf, rcu);
1675
1676 btf_free(btf);
1677}
1678
1679void btf_get(struct btf *btf)
1680{
1681 refcount_inc(&btf->refcnt);
1682}
1683
1684void btf_put(struct btf *btf)
1685{
1686 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1687 btf_free_id(btf);
1688 call_rcu(&btf->rcu, btf_free_rcu);
1689 }
1690}
1691
1692static int env_resolve_init(struct btf_verifier_env *env)
1693{
1694 struct btf *btf = env->btf;
1695 u32 nr_types = btf->nr_types;
1696 u32 *resolved_sizes = NULL;
1697 u32 *resolved_ids = NULL;
1698 u8 *visit_states = NULL;
1699
1700 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1701 GFP_KERNEL | __GFP_NOWARN);
1702 if (!resolved_sizes)
1703 goto nomem;
1704
1705 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1706 GFP_KERNEL | __GFP_NOWARN);
1707 if (!resolved_ids)
1708 goto nomem;
1709
1710 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1711 GFP_KERNEL | __GFP_NOWARN);
1712 if (!visit_states)
1713 goto nomem;
1714
1715 btf->resolved_sizes = resolved_sizes;
1716 btf->resolved_ids = resolved_ids;
1717 env->visit_states = visit_states;
1718
1719 return 0;
1720
1721nomem:
1722 kvfree(resolved_sizes);
1723 kvfree(resolved_ids);
1724 kvfree(visit_states);
1725 return -ENOMEM;
1726}
1727
1728static void btf_verifier_env_free(struct btf_verifier_env *env)
1729{
1730 kvfree(env->visit_states);
1731 kfree(env);
1732}
1733
1734static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1735 const struct btf_type *next_type)
1736{
1737 switch (env->resolve_mode) {
1738 case RESOLVE_TBD:
1739 /* int, enum or void is a sink */
1740 return !btf_type_needs_resolve(next_type);
1741 case RESOLVE_PTR:
1742 /* int, enum, void, struct, array, func or func_proto is a sink
1743 * for ptr
1744 */
1745 return !btf_type_is_modifier(next_type) &&
1746 !btf_type_is_ptr(next_type);
1747 case RESOLVE_STRUCT_OR_ARRAY:
1748 /* int, enum, void, ptr, func or func_proto is a sink
1749 * for struct and array
1750 */
1751 return !btf_type_is_modifier(next_type) &&
1752 !btf_type_is_array(next_type) &&
1753 !btf_type_is_struct(next_type);
1754 default:
1755 BUG();
1756 }
1757}
1758
1759static bool env_type_is_resolved(const struct btf_verifier_env *env,
1760 u32 type_id)
1761{
1762 /* base BTF types should be resolved by now */
1763 if (type_id < env->btf->start_id)
1764 return true;
1765
1766 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1767}
1768
1769static int env_stack_push(struct btf_verifier_env *env,
1770 const struct btf_type *t, u32 type_id)
1771{
1772 const struct btf *btf = env->btf;
1773 struct resolve_vertex *v;
1774
1775 if (env->top_stack == MAX_RESOLVE_DEPTH)
1776 return -E2BIG;
1777
1778 if (type_id < btf->start_id
1779 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1780 return -EEXIST;
1781
1782 env->visit_states[type_id - btf->start_id] = VISITED;
1783
1784 v = &env->stack[env->top_stack++];
1785 v->t = t;
1786 v->type_id = type_id;
1787 v->next_member = 0;
1788
1789 if (env->resolve_mode == RESOLVE_TBD) {
1790 if (btf_type_is_ptr(t))
1791 env->resolve_mode = RESOLVE_PTR;
1792 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1793 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1794 }
1795
1796 return 0;
1797}
1798
1799static void env_stack_set_next_member(struct btf_verifier_env *env,
1800 u16 next_member)
1801{
1802 env->stack[env->top_stack - 1].next_member = next_member;
1803}
1804
1805static void env_stack_pop_resolved(struct btf_verifier_env *env,
1806 u32 resolved_type_id,
1807 u32 resolved_size)
1808{
1809 u32 type_id = env->stack[--(env->top_stack)].type_id;
1810 struct btf *btf = env->btf;
1811
1812 type_id -= btf->start_id; /* adjust to local type id */
1813 btf->resolved_sizes[type_id] = resolved_size;
1814 btf->resolved_ids[type_id] = resolved_type_id;
1815 env->visit_states[type_id] = RESOLVED;
1816}
1817
1818static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1819{
1820 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1821}
1822
1823/* Resolve the size of a passed-in "type"
1824 *
1825 * type: is an array (e.g. u32 array[x][y])
1826 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1827 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1828 * corresponds to the return type.
1829 * *elem_type: u32
1830 * *elem_id: id of u32
1831 * *total_nelems: (x * y). Hence, individual elem size is
1832 * (*type_size / *total_nelems)
1833 * *type_id: id of type if it's changed within the function, 0 if not
1834 *
1835 * type: is not an array (e.g. const struct X)
1836 * return type: type "struct X"
1837 * *type_size: sizeof(struct X)
1838 * *elem_type: same as return type ("struct X")
1839 * *elem_id: 0
1840 * *total_nelems: 1
1841 * *type_id: id of type if it's changed within the function, 0 if not
1842 */
1843static const struct btf_type *
1844__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1845 u32 *type_size, const struct btf_type **elem_type,
1846 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1847{
1848 const struct btf_type *array_type = NULL;
1849 const struct btf_array *array = NULL;
1850 u32 i, size, nelems = 1, id = 0;
1851
1852 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1853 switch (BTF_INFO_KIND(type->info)) {
1854 /* type->size can be used */
1855 case BTF_KIND_INT:
1856 case BTF_KIND_STRUCT:
1857 case BTF_KIND_UNION:
1858 case BTF_KIND_ENUM:
1859 case BTF_KIND_FLOAT:
1860 case BTF_KIND_ENUM64:
1861 size = type->size;
1862 goto resolved;
1863
1864 case BTF_KIND_PTR:
1865 size = sizeof(void *);
1866 goto resolved;
1867
1868 /* Modifiers */
1869 case BTF_KIND_TYPEDEF:
1870 case BTF_KIND_VOLATILE:
1871 case BTF_KIND_CONST:
1872 case BTF_KIND_RESTRICT:
1873 case BTF_KIND_TYPE_TAG:
1874 id = type->type;
1875 type = btf_type_by_id(btf, type->type);
1876 break;
1877
1878 case BTF_KIND_ARRAY:
1879 if (!array_type)
1880 array_type = type;
1881 array = btf_type_array(type);
1882 if (nelems && array->nelems > U32_MAX / nelems)
1883 return ERR_PTR(-EINVAL);
1884 nelems *= array->nelems;
1885 type = btf_type_by_id(btf, array->type);
1886 break;
1887
1888 /* type without size */
1889 default:
1890 return ERR_PTR(-EINVAL);
1891 }
1892 }
1893
1894 return ERR_PTR(-EINVAL);
1895
1896resolved:
1897 if (nelems && size > U32_MAX / nelems)
1898 return ERR_PTR(-EINVAL);
1899
1900 *type_size = nelems * size;
1901 if (total_nelems)
1902 *total_nelems = nelems;
1903 if (elem_type)
1904 *elem_type = type;
1905 if (elem_id)
1906 *elem_id = array ? array->type : 0;
1907 if (type_id && id)
1908 *type_id = id;
1909
1910 return array_type ? : type;
1911}
1912
1913const struct btf_type *
1914btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1915 u32 *type_size)
1916{
1917 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1918}
1919
1920static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1921{
1922 while (type_id < btf->start_id)
1923 btf = btf->base_btf;
1924
1925 return btf->resolved_ids[type_id - btf->start_id];
1926}
1927
1928/* The input param "type_id" must point to a needs_resolve type */
1929static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1930 u32 *type_id)
1931{
1932 *type_id = btf_resolved_type_id(btf, *type_id);
1933 return btf_type_by_id(btf, *type_id);
1934}
1935
1936static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1937{
1938 while (type_id < btf->start_id)
1939 btf = btf->base_btf;
1940
1941 return btf->resolved_sizes[type_id - btf->start_id];
1942}
1943
1944const struct btf_type *btf_type_id_size(const struct btf *btf,
1945 u32 *type_id, u32 *ret_size)
1946{
1947 const struct btf_type *size_type;
1948 u32 size_type_id = *type_id;
1949 u32 size = 0;
1950
1951 size_type = btf_type_by_id(btf, size_type_id);
1952 if (btf_type_nosize_or_null(size_type))
1953 return NULL;
1954
1955 if (btf_type_has_size(size_type)) {
1956 size = size_type->size;
1957 } else if (btf_type_is_array(size_type)) {
1958 size = btf_resolved_type_size(btf, size_type_id);
1959 } else if (btf_type_is_ptr(size_type)) {
1960 size = sizeof(void *);
1961 } else {
1962 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1963 !btf_type_is_var(size_type)))
1964 return NULL;
1965
1966 size_type_id = btf_resolved_type_id(btf, size_type_id);
1967 size_type = btf_type_by_id(btf, size_type_id);
1968 if (btf_type_nosize_or_null(size_type))
1969 return NULL;
1970 else if (btf_type_has_size(size_type))
1971 size = size_type->size;
1972 else if (btf_type_is_array(size_type))
1973 size = btf_resolved_type_size(btf, size_type_id);
1974 else if (btf_type_is_ptr(size_type))
1975 size = sizeof(void *);
1976 else
1977 return NULL;
1978 }
1979
1980 *type_id = size_type_id;
1981 if (ret_size)
1982 *ret_size = size;
1983
1984 return size_type;
1985}
1986
1987static int btf_df_check_member(struct btf_verifier_env *env,
1988 const struct btf_type *struct_type,
1989 const struct btf_member *member,
1990 const struct btf_type *member_type)
1991{
1992 btf_verifier_log_basic(env, struct_type,
1993 "Unsupported check_member");
1994 return -EINVAL;
1995}
1996
1997static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1998 const struct btf_type *struct_type,
1999 const struct btf_member *member,
2000 const struct btf_type *member_type)
2001{
2002 btf_verifier_log_basic(env, struct_type,
2003 "Unsupported check_kflag_member");
2004 return -EINVAL;
2005}
2006
2007/* Used for ptr, array struct/union and float type members.
2008 * int, enum and modifier types have their specific callback functions.
2009 */
2010static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2011 const struct btf_type *struct_type,
2012 const struct btf_member *member,
2013 const struct btf_type *member_type)
2014{
2015 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2016 btf_verifier_log_member(env, struct_type, member,
2017 "Invalid member bitfield_size");
2018 return -EINVAL;
2019 }
2020
2021 /* bitfield size is 0, so member->offset represents bit offset only.
2022 * It is safe to call non kflag check_member variants.
2023 */
2024 return btf_type_ops(member_type)->check_member(env, struct_type,
2025 member,
2026 member_type);
2027}
2028
2029static int btf_df_resolve(struct btf_verifier_env *env,
2030 const struct resolve_vertex *v)
2031{
2032 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2033 return -EINVAL;
2034}
2035
2036static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2037 u32 type_id, void *data, u8 bits_offsets,
2038 struct btf_show *show)
2039{
2040 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2041}
2042
2043static int btf_int_check_member(struct btf_verifier_env *env,
2044 const struct btf_type *struct_type,
2045 const struct btf_member *member,
2046 const struct btf_type *member_type)
2047{
2048 u32 int_data = btf_type_int(member_type);
2049 u32 struct_bits_off = member->offset;
2050 u32 struct_size = struct_type->size;
2051 u32 nr_copy_bits;
2052 u32 bytes_offset;
2053
2054 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2055 btf_verifier_log_member(env, struct_type, member,
2056 "bits_offset exceeds U32_MAX");
2057 return -EINVAL;
2058 }
2059
2060 struct_bits_off += BTF_INT_OFFSET(int_data);
2061 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2062 nr_copy_bits = BTF_INT_BITS(int_data) +
2063 BITS_PER_BYTE_MASKED(struct_bits_off);
2064
2065 if (nr_copy_bits > BITS_PER_U128) {
2066 btf_verifier_log_member(env, struct_type, member,
2067 "nr_copy_bits exceeds 128");
2068 return -EINVAL;
2069 }
2070
2071 if (struct_size < bytes_offset ||
2072 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2073 btf_verifier_log_member(env, struct_type, member,
2074 "Member exceeds struct_size");
2075 return -EINVAL;
2076 }
2077
2078 return 0;
2079}
2080
2081static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2082 const struct btf_type *struct_type,
2083 const struct btf_member *member,
2084 const struct btf_type *member_type)
2085{
2086 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2087 u32 int_data = btf_type_int(member_type);
2088 u32 struct_size = struct_type->size;
2089 u32 nr_copy_bits;
2090
2091 /* a regular int type is required for the kflag int member */
2092 if (!btf_type_int_is_regular(member_type)) {
2093 btf_verifier_log_member(env, struct_type, member,
2094 "Invalid member base type");
2095 return -EINVAL;
2096 }
2097
2098 /* check sanity of bitfield size */
2099 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2100 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2101 nr_int_data_bits = BTF_INT_BITS(int_data);
2102 if (!nr_bits) {
2103 /* Not a bitfield member, member offset must be at byte
2104 * boundary.
2105 */
2106 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2107 btf_verifier_log_member(env, struct_type, member,
2108 "Invalid member offset");
2109 return -EINVAL;
2110 }
2111
2112 nr_bits = nr_int_data_bits;
2113 } else if (nr_bits > nr_int_data_bits) {
2114 btf_verifier_log_member(env, struct_type, member,
2115 "Invalid member bitfield_size");
2116 return -EINVAL;
2117 }
2118
2119 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2120 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2121 if (nr_copy_bits > BITS_PER_U128) {
2122 btf_verifier_log_member(env, struct_type, member,
2123 "nr_copy_bits exceeds 128");
2124 return -EINVAL;
2125 }
2126
2127 if (struct_size < bytes_offset ||
2128 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2129 btf_verifier_log_member(env, struct_type, member,
2130 "Member exceeds struct_size");
2131 return -EINVAL;
2132 }
2133
2134 return 0;
2135}
2136
2137static s32 btf_int_check_meta(struct btf_verifier_env *env,
2138 const struct btf_type *t,
2139 u32 meta_left)
2140{
2141 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2142 u16 encoding;
2143
2144 if (meta_left < meta_needed) {
2145 btf_verifier_log_basic(env, t,
2146 "meta_left:%u meta_needed:%u",
2147 meta_left, meta_needed);
2148 return -EINVAL;
2149 }
2150
2151 if (btf_type_vlen(t)) {
2152 btf_verifier_log_type(env, t, "vlen != 0");
2153 return -EINVAL;
2154 }
2155
2156 if (btf_type_kflag(t)) {
2157 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2158 return -EINVAL;
2159 }
2160
2161 int_data = btf_type_int(t);
2162 if (int_data & ~BTF_INT_MASK) {
2163 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2164 int_data);
2165 return -EINVAL;
2166 }
2167
2168 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2169
2170 if (nr_bits > BITS_PER_U128) {
2171 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2172 BITS_PER_U128);
2173 return -EINVAL;
2174 }
2175
2176 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2177 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2178 return -EINVAL;
2179 }
2180
2181 /*
2182 * Only one of the encoding bits is allowed and it
2183 * should be sufficient for the pretty print purpose (i.e. decoding).
2184 * Multiple bits can be allowed later if it is found
2185 * to be insufficient.
2186 */
2187 encoding = BTF_INT_ENCODING(int_data);
2188 if (encoding &&
2189 encoding != BTF_INT_SIGNED &&
2190 encoding != BTF_INT_CHAR &&
2191 encoding != BTF_INT_BOOL) {
2192 btf_verifier_log_type(env, t, "Unsupported encoding");
2193 return -ENOTSUPP;
2194 }
2195
2196 btf_verifier_log_type(env, t, NULL);
2197
2198 return meta_needed;
2199}
2200
2201static void btf_int_log(struct btf_verifier_env *env,
2202 const struct btf_type *t)
2203{
2204 int int_data = btf_type_int(t);
2205
2206 btf_verifier_log(env,
2207 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2208 t->size, BTF_INT_OFFSET(int_data),
2209 BTF_INT_BITS(int_data),
2210 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2211}
2212
2213static void btf_int128_print(struct btf_show *show, void *data)
2214{
2215 /* data points to a __int128 number.
2216 * Suppose
2217 * int128_num = *(__int128 *)data;
2218 * The below formulas shows what upper_num and lower_num represents:
2219 * upper_num = int128_num >> 64;
2220 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2221 */
2222 u64 upper_num, lower_num;
2223
2224#ifdef __BIG_ENDIAN_BITFIELD
2225 upper_num = *(u64 *)data;
2226 lower_num = *(u64 *)(data + 8);
2227#else
2228 upper_num = *(u64 *)(data + 8);
2229 lower_num = *(u64 *)data;
2230#endif
2231 if (upper_num == 0)
2232 btf_show_type_value(show, "0x%llx", lower_num);
2233 else
2234 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2235 lower_num);
2236}
2237
2238static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2239 u16 right_shift_bits)
2240{
2241 u64 upper_num, lower_num;
2242
2243#ifdef __BIG_ENDIAN_BITFIELD
2244 upper_num = print_num[0];
2245 lower_num = print_num[1];
2246#else
2247 upper_num = print_num[1];
2248 lower_num = print_num[0];
2249#endif
2250
2251 /* shake out un-needed bits by shift/or operations */
2252 if (left_shift_bits >= 64) {
2253 upper_num = lower_num << (left_shift_bits - 64);
2254 lower_num = 0;
2255 } else {
2256 upper_num = (upper_num << left_shift_bits) |
2257 (lower_num >> (64 - left_shift_bits));
2258 lower_num = lower_num << left_shift_bits;
2259 }
2260
2261 if (right_shift_bits >= 64) {
2262 lower_num = upper_num >> (right_shift_bits - 64);
2263 upper_num = 0;
2264 } else {
2265 lower_num = (lower_num >> right_shift_bits) |
2266 (upper_num << (64 - right_shift_bits));
2267 upper_num = upper_num >> right_shift_bits;
2268 }
2269
2270#ifdef __BIG_ENDIAN_BITFIELD
2271 print_num[0] = upper_num;
2272 print_num[1] = lower_num;
2273#else
2274 print_num[0] = lower_num;
2275 print_num[1] = upper_num;
2276#endif
2277}
2278
2279static void btf_bitfield_show(void *data, u8 bits_offset,
2280 u8 nr_bits, struct btf_show *show)
2281{
2282 u16 left_shift_bits, right_shift_bits;
2283 u8 nr_copy_bytes;
2284 u8 nr_copy_bits;
2285 u64 print_num[2] = {};
2286
2287 nr_copy_bits = nr_bits + bits_offset;
2288 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2289
2290 memcpy(print_num, data, nr_copy_bytes);
2291
2292#ifdef __BIG_ENDIAN_BITFIELD
2293 left_shift_bits = bits_offset;
2294#else
2295 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2296#endif
2297 right_shift_bits = BITS_PER_U128 - nr_bits;
2298
2299 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2300 btf_int128_print(show, print_num);
2301}
2302
2303
2304static void btf_int_bits_show(const struct btf *btf,
2305 const struct btf_type *t,
2306 void *data, u8 bits_offset,
2307 struct btf_show *show)
2308{
2309 u32 int_data = btf_type_int(t);
2310 u8 nr_bits = BTF_INT_BITS(int_data);
2311 u8 total_bits_offset;
2312
2313 /*
2314 * bits_offset is at most 7.
2315 * BTF_INT_OFFSET() cannot exceed 128 bits.
2316 */
2317 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2318 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2319 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2320 btf_bitfield_show(data, bits_offset, nr_bits, show);
2321}
2322
2323static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2324 u32 type_id, void *data, u8 bits_offset,
2325 struct btf_show *show)
2326{
2327 u32 int_data = btf_type_int(t);
2328 u8 encoding = BTF_INT_ENCODING(int_data);
2329 bool sign = encoding & BTF_INT_SIGNED;
2330 u8 nr_bits = BTF_INT_BITS(int_data);
2331 void *safe_data;
2332
2333 safe_data = btf_show_start_type(show, t, type_id, data);
2334 if (!safe_data)
2335 return;
2336
2337 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2338 BITS_PER_BYTE_MASKED(nr_bits)) {
2339 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2340 goto out;
2341 }
2342
2343 switch (nr_bits) {
2344 case 128:
2345 btf_int128_print(show, safe_data);
2346 break;
2347 case 64:
2348 if (sign)
2349 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2350 else
2351 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2352 break;
2353 case 32:
2354 if (sign)
2355 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2356 else
2357 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2358 break;
2359 case 16:
2360 if (sign)
2361 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2362 else
2363 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2364 break;
2365 case 8:
2366 if (show->state.array_encoding == BTF_INT_CHAR) {
2367 /* check for null terminator */
2368 if (show->state.array_terminated)
2369 break;
2370 if (*(char *)data == '\0') {
2371 show->state.array_terminated = 1;
2372 break;
2373 }
2374 if (isprint(*(char *)data)) {
2375 btf_show_type_value(show, "'%c'",
2376 *(char *)safe_data);
2377 break;
2378 }
2379 }
2380 if (sign)
2381 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2382 else
2383 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2384 break;
2385 default:
2386 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2387 break;
2388 }
2389out:
2390 btf_show_end_type(show);
2391}
2392
2393static const struct btf_kind_operations int_ops = {
2394 .check_meta = btf_int_check_meta,
2395 .resolve = btf_df_resolve,
2396 .check_member = btf_int_check_member,
2397 .check_kflag_member = btf_int_check_kflag_member,
2398 .log_details = btf_int_log,
2399 .show = btf_int_show,
2400};
2401
2402static int btf_modifier_check_member(struct btf_verifier_env *env,
2403 const struct btf_type *struct_type,
2404 const struct btf_member *member,
2405 const struct btf_type *member_type)
2406{
2407 const struct btf_type *resolved_type;
2408 u32 resolved_type_id = member->type;
2409 struct btf_member resolved_member;
2410 struct btf *btf = env->btf;
2411
2412 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2413 if (!resolved_type) {
2414 btf_verifier_log_member(env, struct_type, member,
2415 "Invalid member");
2416 return -EINVAL;
2417 }
2418
2419 resolved_member = *member;
2420 resolved_member.type = resolved_type_id;
2421
2422 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2423 &resolved_member,
2424 resolved_type);
2425}
2426
2427static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2428 const struct btf_type *struct_type,
2429 const struct btf_member *member,
2430 const struct btf_type *member_type)
2431{
2432 const struct btf_type *resolved_type;
2433 u32 resolved_type_id = member->type;
2434 struct btf_member resolved_member;
2435 struct btf *btf = env->btf;
2436
2437 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2438 if (!resolved_type) {
2439 btf_verifier_log_member(env, struct_type, member,
2440 "Invalid member");
2441 return -EINVAL;
2442 }
2443
2444 resolved_member = *member;
2445 resolved_member.type = resolved_type_id;
2446
2447 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2448 &resolved_member,
2449 resolved_type);
2450}
2451
2452static int btf_ptr_check_member(struct btf_verifier_env *env,
2453 const struct btf_type *struct_type,
2454 const struct btf_member *member,
2455 const struct btf_type *member_type)
2456{
2457 u32 struct_size, struct_bits_off, bytes_offset;
2458
2459 struct_size = struct_type->size;
2460 struct_bits_off = member->offset;
2461 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2462
2463 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2464 btf_verifier_log_member(env, struct_type, member,
2465 "Member is not byte aligned");
2466 return -EINVAL;
2467 }
2468
2469 if (struct_size - bytes_offset < sizeof(void *)) {
2470 btf_verifier_log_member(env, struct_type, member,
2471 "Member exceeds struct_size");
2472 return -EINVAL;
2473 }
2474
2475 return 0;
2476}
2477
2478static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2479 const struct btf_type *t,
2480 u32 meta_left)
2481{
2482 const char *value;
2483
2484 if (btf_type_vlen(t)) {
2485 btf_verifier_log_type(env, t, "vlen != 0");
2486 return -EINVAL;
2487 }
2488
2489 if (btf_type_kflag(t)) {
2490 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2491 return -EINVAL;
2492 }
2493
2494 if (!BTF_TYPE_ID_VALID(t->type)) {
2495 btf_verifier_log_type(env, t, "Invalid type_id");
2496 return -EINVAL;
2497 }
2498
2499 /* typedef/type_tag type must have a valid name, and other ref types,
2500 * volatile, const, restrict, should have a null name.
2501 */
2502 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2503 if (!t->name_off ||
2504 !btf_name_valid_identifier(env->btf, t->name_off)) {
2505 btf_verifier_log_type(env, t, "Invalid name");
2506 return -EINVAL;
2507 }
2508 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2509 value = btf_name_by_offset(env->btf, t->name_off);
2510 if (!value || !value[0]) {
2511 btf_verifier_log_type(env, t, "Invalid name");
2512 return -EINVAL;
2513 }
2514 } else {
2515 if (t->name_off) {
2516 btf_verifier_log_type(env, t, "Invalid name");
2517 return -EINVAL;
2518 }
2519 }
2520
2521 btf_verifier_log_type(env, t, NULL);
2522
2523 return 0;
2524}
2525
2526static int btf_modifier_resolve(struct btf_verifier_env *env,
2527 const struct resolve_vertex *v)
2528{
2529 const struct btf_type *t = v->t;
2530 const struct btf_type *next_type;
2531 u32 next_type_id = t->type;
2532 struct btf *btf = env->btf;
2533
2534 next_type = btf_type_by_id(btf, next_type_id);
2535 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2536 btf_verifier_log_type(env, v->t, "Invalid type_id");
2537 return -EINVAL;
2538 }
2539
2540 if (!env_type_is_resolve_sink(env, next_type) &&
2541 !env_type_is_resolved(env, next_type_id))
2542 return env_stack_push(env, next_type, next_type_id);
2543
2544 /* Figure out the resolved next_type_id with size.
2545 * They will be stored in the current modifier's
2546 * resolved_ids and resolved_sizes such that it can
2547 * save us a few type-following when we use it later (e.g. in
2548 * pretty print).
2549 */
2550 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2551 if (env_type_is_resolved(env, next_type_id))
2552 next_type = btf_type_id_resolve(btf, &next_type_id);
2553
2554 /* "typedef void new_void", "const void"...etc */
2555 if (!btf_type_is_void(next_type) &&
2556 !btf_type_is_fwd(next_type) &&
2557 !btf_type_is_func_proto(next_type)) {
2558 btf_verifier_log_type(env, v->t, "Invalid type_id");
2559 return -EINVAL;
2560 }
2561 }
2562
2563 env_stack_pop_resolved(env, next_type_id, 0);
2564
2565 return 0;
2566}
2567
2568static int btf_var_resolve(struct btf_verifier_env *env,
2569 const struct resolve_vertex *v)
2570{
2571 const struct btf_type *next_type;
2572 const struct btf_type *t = v->t;
2573 u32 next_type_id = t->type;
2574 struct btf *btf = env->btf;
2575
2576 next_type = btf_type_by_id(btf, next_type_id);
2577 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2578 btf_verifier_log_type(env, v->t, "Invalid type_id");
2579 return -EINVAL;
2580 }
2581
2582 if (!env_type_is_resolve_sink(env, next_type) &&
2583 !env_type_is_resolved(env, next_type_id))
2584 return env_stack_push(env, next_type, next_type_id);
2585
2586 if (btf_type_is_modifier(next_type)) {
2587 const struct btf_type *resolved_type;
2588 u32 resolved_type_id;
2589
2590 resolved_type_id = next_type_id;
2591 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2592
2593 if (btf_type_is_ptr(resolved_type) &&
2594 !env_type_is_resolve_sink(env, resolved_type) &&
2595 !env_type_is_resolved(env, resolved_type_id))
2596 return env_stack_push(env, resolved_type,
2597 resolved_type_id);
2598 }
2599
2600 /* We must resolve to something concrete at this point, no
2601 * forward types or similar that would resolve to size of
2602 * zero is allowed.
2603 */
2604 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2605 btf_verifier_log_type(env, v->t, "Invalid type_id");
2606 return -EINVAL;
2607 }
2608
2609 env_stack_pop_resolved(env, next_type_id, 0);
2610
2611 return 0;
2612}
2613
2614static int btf_ptr_resolve(struct btf_verifier_env *env,
2615 const struct resolve_vertex *v)
2616{
2617 const struct btf_type *next_type;
2618 const struct btf_type *t = v->t;
2619 u32 next_type_id = t->type;
2620 struct btf *btf = env->btf;
2621
2622 next_type = btf_type_by_id(btf, next_type_id);
2623 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2624 btf_verifier_log_type(env, v->t, "Invalid type_id");
2625 return -EINVAL;
2626 }
2627
2628 if (!env_type_is_resolve_sink(env, next_type) &&
2629 !env_type_is_resolved(env, next_type_id))
2630 return env_stack_push(env, next_type, next_type_id);
2631
2632 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2633 * the modifier may have stopped resolving when it was resolved
2634 * to a ptr (last-resolved-ptr).
2635 *
2636 * We now need to continue from the last-resolved-ptr to
2637 * ensure the last-resolved-ptr will not referring back to
2638 * the current ptr (t).
2639 */
2640 if (btf_type_is_modifier(next_type)) {
2641 const struct btf_type *resolved_type;
2642 u32 resolved_type_id;
2643
2644 resolved_type_id = next_type_id;
2645 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2646
2647 if (btf_type_is_ptr(resolved_type) &&
2648 !env_type_is_resolve_sink(env, resolved_type) &&
2649 !env_type_is_resolved(env, resolved_type_id))
2650 return env_stack_push(env, resolved_type,
2651 resolved_type_id);
2652 }
2653
2654 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2655 if (env_type_is_resolved(env, next_type_id))
2656 next_type = btf_type_id_resolve(btf, &next_type_id);
2657
2658 if (!btf_type_is_void(next_type) &&
2659 !btf_type_is_fwd(next_type) &&
2660 !btf_type_is_func_proto(next_type)) {
2661 btf_verifier_log_type(env, v->t, "Invalid type_id");
2662 return -EINVAL;
2663 }
2664 }
2665
2666 env_stack_pop_resolved(env, next_type_id, 0);
2667
2668 return 0;
2669}
2670
2671static void btf_modifier_show(const struct btf *btf,
2672 const struct btf_type *t,
2673 u32 type_id, void *data,
2674 u8 bits_offset, struct btf_show *show)
2675{
2676 if (btf->resolved_ids)
2677 t = btf_type_id_resolve(btf, &type_id);
2678 else
2679 t = btf_type_skip_modifiers(btf, type_id, NULL);
2680
2681 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2682}
2683
2684static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2685 u32 type_id, void *data, u8 bits_offset,
2686 struct btf_show *show)
2687{
2688 t = btf_type_id_resolve(btf, &type_id);
2689
2690 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2691}
2692
2693static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2694 u32 type_id, void *data, u8 bits_offset,
2695 struct btf_show *show)
2696{
2697 void *safe_data;
2698
2699 safe_data = btf_show_start_type(show, t, type_id, data);
2700 if (!safe_data)
2701 return;
2702
2703 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2704 if (show->flags & BTF_SHOW_PTR_RAW)
2705 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2706 else
2707 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2708 btf_show_end_type(show);
2709}
2710
2711static void btf_ref_type_log(struct btf_verifier_env *env,
2712 const struct btf_type *t)
2713{
2714 btf_verifier_log(env, "type_id=%u", t->type);
2715}
2716
2717static struct btf_kind_operations modifier_ops = {
2718 .check_meta = btf_ref_type_check_meta,
2719 .resolve = btf_modifier_resolve,
2720 .check_member = btf_modifier_check_member,
2721 .check_kflag_member = btf_modifier_check_kflag_member,
2722 .log_details = btf_ref_type_log,
2723 .show = btf_modifier_show,
2724};
2725
2726static struct btf_kind_operations ptr_ops = {
2727 .check_meta = btf_ref_type_check_meta,
2728 .resolve = btf_ptr_resolve,
2729 .check_member = btf_ptr_check_member,
2730 .check_kflag_member = btf_generic_check_kflag_member,
2731 .log_details = btf_ref_type_log,
2732 .show = btf_ptr_show,
2733};
2734
2735static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2736 const struct btf_type *t,
2737 u32 meta_left)
2738{
2739 if (btf_type_vlen(t)) {
2740 btf_verifier_log_type(env, t, "vlen != 0");
2741 return -EINVAL;
2742 }
2743
2744 if (t->type) {
2745 btf_verifier_log_type(env, t, "type != 0");
2746 return -EINVAL;
2747 }
2748
2749 /* fwd type must have a valid name */
2750 if (!t->name_off ||
2751 !btf_name_valid_identifier(env->btf, t->name_off)) {
2752 btf_verifier_log_type(env, t, "Invalid name");
2753 return -EINVAL;
2754 }
2755
2756 btf_verifier_log_type(env, t, NULL);
2757
2758 return 0;
2759}
2760
2761static void btf_fwd_type_log(struct btf_verifier_env *env,
2762 const struct btf_type *t)
2763{
2764 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2765}
2766
2767static struct btf_kind_operations fwd_ops = {
2768 .check_meta = btf_fwd_check_meta,
2769 .resolve = btf_df_resolve,
2770 .check_member = btf_df_check_member,
2771 .check_kflag_member = btf_df_check_kflag_member,
2772 .log_details = btf_fwd_type_log,
2773 .show = btf_df_show,
2774};
2775
2776static int btf_array_check_member(struct btf_verifier_env *env,
2777 const struct btf_type *struct_type,
2778 const struct btf_member *member,
2779 const struct btf_type *member_type)
2780{
2781 u32 struct_bits_off = member->offset;
2782 u32 struct_size, bytes_offset;
2783 u32 array_type_id, array_size;
2784 struct btf *btf = env->btf;
2785
2786 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2787 btf_verifier_log_member(env, struct_type, member,
2788 "Member is not byte aligned");
2789 return -EINVAL;
2790 }
2791
2792 array_type_id = member->type;
2793 btf_type_id_size(btf, &array_type_id, &array_size);
2794 struct_size = struct_type->size;
2795 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2796 if (struct_size - bytes_offset < array_size) {
2797 btf_verifier_log_member(env, struct_type, member,
2798 "Member exceeds struct_size");
2799 return -EINVAL;
2800 }
2801
2802 return 0;
2803}
2804
2805static s32 btf_array_check_meta(struct btf_verifier_env *env,
2806 const struct btf_type *t,
2807 u32 meta_left)
2808{
2809 const struct btf_array *array = btf_type_array(t);
2810 u32 meta_needed = sizeof(*array);
2811
2812 if (meta_left < meta_needed) {
2813 btf_verifier_log_basic(env, t,
2814 "meta_left:%u meta_needed:%u",
2815 meta_left, meta_needed);
2816 return -EINVAL;
2817 }
2818
2819 /* array type should not have a name */
2820 if (t->name_off) {
2821 btf_verifier_log_type(env, t, "Invalid name");
2822 return -EINVAL;
2823 }
2824
2825 if (btf_type_vlen(t)) {
2826 btf_verifier_log_type(env, t, "vlen != 0");
2827 return -EINVAL;
2828 }
2829
2830 if (btf_type_kflag(t)) {
2831 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2832 return -EINVAL;
2833 }
2834
2835 if (t->size) {
2836 btf_verifier_log_type(env, t, "size != 0");
2837 return -EINVAL;
2838 }
2839
2840 /* Array elem type and index type cannot be in type void,
2841 * so !array->type and !array->index_type are not allowed.
2842 */
2843 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2844 btf_verifier_log_type(env, t, "Invalid elem");
2845 return -EINVAL;
2846 }
2847
2848 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2849 btf_verifier_log_type(env, t, "Invalid index");
2850 return -EINVAL;
2851 }
2852
2853 btf_verifier_log_type(env, t, NULL);
2854
2855 return meta_needed;
2856}
2857
2858static int btf_array_resolve(struct btf_verifier_env *env,
2859 const struct resolve_vertex *v)
2860{
2861 const struct btf_array *array = btf_type_array(v->t);
2862 const struct btf_type *elem_type, *index_type;
2863 u32 elem_type_id, index_type_id;
2864 struct btf *btf = env->btf;
2865 u32 elem_size;
2866
2867 /* Check array->index_type */
2868 index_type_id = array->index_type;
2869 index_type = btf_type_by_id(btf, index_type_id);
2870 if (btf_type_nosize_or_null(index_type) ||
2871 btf_type_is_resolve_source_only(index_type)) {
2872 btf_verifier_log_type(env, v->t, "Invalid index");
2873 return -EINVAL;
2874 }
2875
2876 if (!env_type_is_resolve_sink(env, index_type) &&
2877 !env_type_is_resolved(env, index_type_id))
2878 return env_stack_push(env, index_type, index_type_id);
2879
2880 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2881 if (!index_type || !btf_type_is_int(index_type) ||
2882 !btf_type_int_is_regular(index_type)) {
2883 btf_verifier_log_type(env, v->t, "Invalid index");
2884 return -EINVAL;
2885 }
2886
2887 /* Check array->type */
2888 elem_type_id = array->type;
2889 elem_type = btf_type_by_id(btf, elem_type_id);
2890 if (btf_type_nosize_or_null(elem_type) ||
2891 btf_type_is_resolve_source_only(elem_type)) {
2892 btf_verifier_log_type(env, v->t,
2893 "Invalid elem");
2894 return -EINVAL;
2895 }
2896
2897 if (!env_type_is_resolve_sink(env, elem_type) &&
2898 !env_type_is_resolved(env, elem_type_id))
2899 return env_stack_push(env, elem_type, elem_type_id);
2900
2901 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2902 if (!elem_type) {
2903 btf_verifier_log_type(env, v->t, "Invalid elem");
2904 return -EINVAL;
2905 }
2906
2907 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2908 btf_verifier_log_type(env, v->t, "Invalid array of int");
2909 return -EINVAL;
2910 }
2911
2912 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2913 btf_verifier_log_type(env, v->t,
2914 "Array size overflows U32_MAX");
2915 return -EINVAL;
2916 }
2917
2918 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2919
2920 return 0;
2921}
2922
2923static void btf_array_log(struct btf_verifier_env *env,
2924 const struct btf_type *t)
2925{
2926 const struct btf_array *array = btf_type_array(t);
2927
2928 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2929 array->type, array->index_type, array->nelems);
2930}
2931
2932static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2933 u32 type_id, void *data, u8 bits_offset,
2934 struct btf_show *show)
2935{
2936 const struct btf_array *array = btf_type_array(t);
2937 const struct btf_kind_operations *elem_ops;
2938 const struct btf_type *elem_type;
2939 u32 i, elem_size = 0, elem_type_id;
2940 u16 encoding = 0;
2941
2942 elem_type_id = array->type;
2943 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2944 if (elem_type && btf_type_has_size(elem_type))
2945 elem_size = elem_type->size;
2946
2947 if (elem_type && btf_type_is_int(elem_type)) {
2948 u32 int_type = btf_type_int(elem_type);
2949
2950 encoding = BTF_INT_ENCODING(int_type);
2951
2952 /*
2953 * BTF_INT_CHAR encoding never seems to be set for
2954 * char arrays, so if size is 1 and element is
2955 * printable as a char, we'll do that.
2956 */
2957 if (elem_size == 1)
2958 encoding = BTF_INT_CHAR;
2959 }
2960
2961 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2962 return;
2963
2964 if (!elem_type)
2965 goto out;
2966 elem_ops = btf_type_ops(elem_type);
2967
2968 for (i = 0; i < array->nelems; i++) {
2969
2970 btf_show_start_array_member(show);
2971
2972 elem_ops->show(btf, elem_type, elem_type_id, data,
2973 bits_offset, show);
2974 data += elem_size;
2975
2976 btf_show_end_array_member(show);
2977
2978 if (show->state.array_terminated)
2979 break;
2980 }
2981out:
2982 btf_show_end_array_type(show);
2983}
2984
2985static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2986 u32 type_id, void *data, u8 bits_offset,
2987 struct btf_show *show)
2988{
2989 const struct btf_member *m = show->state.member;
2990
2991 /*
2992 * First check if any members would be shown (are non-zero).
2993 * See comments above "struct btf_show" definition for more
2994 * details on how this works at a high-level.
2995 */
2996 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2997 if (!show->state.depth_check) {
2998 show->state.depth_check = show->state.depth + 1;
2999 show->state.depth_to_show = 0;
3000 }
3001 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3002 show->state.member = m;
3003
3004 if (show->state.depth_check != show->state.depth + 1)
3005 return;
3006 show->state.depth_check = 0;
3007
3008 if (show->state.depth_to_show <= show->state.depth)
3009 return;
3010 /*
3011 * Reaching here indicates we have recursed and found
3012 * non-zero array member(s).
3013 */
3014 }
3015 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3016}
3017
3018static struct btf_kind_operations array_ops = {
3019 .check_meta = btf_array_check_meta,
3020 .resolve = btf_array_resolve,
3021 .check_member = btf_array_check_member,
3022 .check_kflag_member = btf_generic_check_kflag_member,
3023 .log_details = btf_array_log,
3024 .show = btf_array_show,
3025};
3026
3027static int btf_struct_check_member(struct btf_verifier_env *env,
3028 const struct btf_type *struct_type,
3029 const struct btf_member *member,
3030 const struct btf_type *member_type)
3031{
3032 u32 struct_bits_off = member->offset;
3033 u32 struct_size, bytes_offset;
3034
3035 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3036 btf_verifier_log_member(env, struct_type, member,
3037 "Member is not byte aligned");
3038 return -EINVAL;
3039 }
3040
3041 struct_size = struct_type->size;
3042 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3043 if (struct_size - bytes_offset < member_type->size) {
3044 btf_verifier_log_member(env, struct_type, member,
3045 "Member exceeds struct_size");
3046 return -EINVAL;
3047 }
3048
3049 return 0;
3050}
3051
3052static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3053 const struct btf_type *t,
3054 u32 meta_left)
3055{
3056 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3057 const struct btf_member *member;
3058 u32 meta_needed, last_offset;
3059 struct btf *btf = env->btf;
3060 u32 struct_size = t->size;
3061 u32 offset;
3062 u16 i;
3063
3064 meta_needed = btf_type_vlen(t) * sizeof(*member);
3065 if (meta_left < meta_needed) {
3066 btf_verifier_log_basic(env, t,
3067 "meta_left:%u meta_needed:%u",
3068 meta_left, meta_needed);
3069 return -EINVAL;
3070 }
3071
3072 /* struct type either no name or a valid one */
3073 if (t->name_off &&
3074 !btf_name_valid_identifier(env->btf, t->name_off)) {
3075 btf_verifier_log_type(env, t, "Invalid name");
3076 return -EINVAL;
3077 }
3078
3079 btf_verifier_log_type(env, t, NULL);
3080
3081 last_offset = 0;
3082 for_each_member(i, t, member) {
3083 if (!btf_name_offset_valid(btf, member->name_off)) {
3084 btf_verifier_log_member(env, t, member,
3085 "Invalid member name_offset:%u",
3086 member->name_off);
3087 return -EINVAL;
3088 }
3089
3090 /* struct member either no name or a valid one */
3091 if (member->name_off &&
3092 !btf_name_valid_identifier(btf, member->name_off)) {
3093 btf_verifier_log_member(env, t, member, "Invalid name");
3094 return -EINVAL;
3095 }
3096 /* A member cannot be in type void */
3097 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3098 btf_verifier_log_member(env, t, member,
3099 "Invalid type_id");
3100 return -EINVAL;
3101 }
3102
3103 offset = __btf_member_bit_offset(t, member);
3104 if (is_union && offset) {
3105 btf_verifier_log_member(env, t, member,
3106 "Invalid member bits_offset");
3107 return -EINVAL;
3108 }
3109
3110 /*
3111 * ">" instead of ">=" because the last member could be
3112 * "char a[0];"
3113 */
3114 if (last_offset > offset) {
3115 btf_verifier_log_member(env, t, member,
3116 "Invalid member bits_offset");
3117 return -EINVAL;
3118 }
3119
3120 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3121 btf_verifier_log_member(env, t, member,
3122 "Member bits_offset exceeds its struct size");
3123 return -EINVAL;
3124 }
3125
3126 btf_verifier_log_member(env, t, member, NULL);
3127 last_offset = offset;
3128 }
3129
3130 return meta_needed;
3131}
3132
3133static int btf_struct_resolve(struct btf_verifier_env *env,
3134 const struct resolve_vertex *v)
3135{
3136 const struct btf_member *member;
3137 int err;
3138 u16 i;
3139
3140 /* Before continue resolving the next_member,
3141 * ensure the last member is indeed resolved to a
3142 * type with size info.
3143 */
3144 if (v->next_member) {
3145 const struct btf_type *last_member_type;
3146 const struct btf_member *last_member;
3147 u32 last_member_type_id;
3148
3149 last_member = btf_type_member(v->t) + v->next_member - 1;
3150 last_member_type_id = last_member->type;
3151 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3152 last_member_type_id)))
3153 return -EINVAL;
3154
3155 last_member_type = btf_type_by_id(env->btf,
3156 last_member_type_id);
3157 if (btf_type_kflag(v->t))
3158 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3159 last_member,
3160 last_member_type);
3161 else
3162 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3163 last_member,
3164 last_member_type);
3165 if (err)
3166 return err;
3167 }
3168
3169 for_each_member_from(i, v->next_member, v->t, member) {
3170 u32 member_type_id = member->type;
3171 const struct btf_type *member_type = btf_type_by_id(env->btf,
3172 member_type_id);
3173
3174 if (btf_type_nosize_or_null(member_type) ||
3175 btf_type_is_resolve_source_only(member_type)) {
3176 btf_verifier_log_member(env, v->t, member,
3177 "Invalid member");
3178 return -EINVAL;
3179 }
3180
3181 if (!env_type_is_resolve_sink(env, member_type) &&
3182 !env_type_is_resolved(env, member_type_id)) {
3183 env_stack_set_next_member(env, i + 1);
3184 return env_stack_push(env, member_type, member_type_id);
3185 }
3186
3187 if (btf_type_kflag(v->t))
3188 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3189 member,
3190 member_type);
3191 else
3192 err = btf_type_ops(member_type)->check_member(env, v->t,
3193 member,
3194 member_type);
3195 if (err)
3196 return err;
3197 }
3198
3199 env_stack_pop_resolved(env, 0, 0);
3200
3201 return 0;
3202}
3203
3204static void btf_struct_log(struct btf_verifier_env *env,
3205 const struct btf_type *t)
3206{
3207 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3208}
3209
3210enum btf_field_info_type {
3211 BTF_FIELD_SPIN_LOCK,
3212 BTF_FIELD_TIMER,
3213 BTF_FIELD_KPTR,
3214};
3215
3216enum {
3217 BTF_FIELD_IGNORE = 0,
3218 BTF_FIELD_FOUND = 1,
3219};
3220
3221struct btf_field_info {
3222 enum btf_field_type type;
3223 u32 off;
3224 union {
3225 struct {
3226 u32 type_id;
3227 } kptr;
3228 struct {
3229 const char *node_name;
3230 u32 value_btf_id;
3231 } list_head;
3232 };
3233};
3234
3235static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3236 u32 off, int sz, enum btf_field_type field_type,
3237 struct btf_field_info *info)
3238{
3239 if (!__btf_type_is_struct(t))
3240 return BTF_FIELD_IGNORE;
3241 if (t->size != sz)
3242 return BTF_FIELD_IGNORE;
3243 info->type = field_type;
3244 info->off = off;
3245 return BTF_FIELD_FOUND;
3246}
3247
3248static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3249 u32 off, int sz, struct btf_field_info *info)
3250{
3251 enum btf_field_type type;
3252 u32 res_id;
3253
3254 /* Permit modifiers on the pointer itself */
3255 if (btf_type_is_volatile(t))
3256 t = btf_type_by_id(btf, t->type);
3257 /* For PTR, sz is always == 8 */
3258 if (!btf_type_is_ptr(t))
3259 return BTF_FIELD_IGNORE;
3260 t = btf_type_by_id(btf, t->type);
3261
3262 if (!btf_type_is_type_tag(t))
3263 return BTF_FIELD_IGNORE;
3264 /* Reject extra tags */
3265 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3266 return -EINVAL;
3267 if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3268 type = BPF_KPTR_UNREF;
3269 else if (!strcmp("kptr_ref", __btf_name_by_offset(btf, t->name_off)))
3270 type = BPF_KPTR_REF;
3271 else
3272 return -EINVAL;
3273
3274 /* Get the base type */
3275 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3276 /* Only pointer to struct is allowed */
3277 if (!__btf_type_is_struct(t))
3278 return -EINVAL;
3279
3280 info->type = type;
3281 info->off = off;
3282 info->kptr.type_id = res_id;
3283 return BTF_FIELD_FOUND;
3284}
3285
3286static const char *btf_find_decl_tag_value(const struct btf *btf,
3287 const struct btf_type *pt,
3288 int comp_idx, const char *tag_key)
3289{
3290 int i;
3291
3292 for (i = 1; i < btf_nr_types(btf); i++) {
3293 const struct btf_type *t = btf_type_by_id(btf, i);
3294 int len = strlen(tag_key);
3295
3296 if (!btf_type_is_decl_tag(t))
3297 continue;
3298 if (pt != btf_type_by_id(btf, t->type) ||
3299 btf_type_decl_tag(t)->component_idx != comp_idx)
3300 continue;
3301 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3302 continue;
3303 return __btf_name_by_offset(btf, t->name_off) + len;
3304 }
3305 return NULL;
3306}
3307
3308static int btf_find_list_head(const struct btf *btf, const struct btf_type *pt,
3309 const struct btf_type *t, int comp_idx,
3310 u32 off, int sz, struct btf_field_info *info)
3311{
3312 const char *value_type;
3313 const char *list_node;
3314 s32 id;
3315
3316 if (!__btf_type_is_struct(t))
3317 return BTF_FIELD_IGNORE;
3318 if (t->size != sz)
3319 return BTF_FIELD_IGNORE;
3320 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3321 if (!value_type)
3322 return -EINVAL;
3323 list_node = strstr(value_type, ":");
3324 if (!list_node)
3325 return -EINVAL;
3326 value_type = kstrndup(value_type, list_node - value_type, GFP_KERNEL | __GFP_NOWARN);
3327 if (!value_type)
3328 return -ENOMEM;
3329 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3330 kfree(value_type);
3331 if (id < 0)
3332 return id;
3333 list_node++;
3334 if (str_is_empty(list_node))
3335 return -EINVAL;
3336 info->type = BPF_LIST_HEAD;
3337 info->off = off;
3338 info->list_head.value_btf_id = id;
3339 info->list_head.node_name = list_node;
3340 return BTF_FIELD_FOUND;
3341}
3342
3343static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
3344 int *align, int *sz)
3345{
3346 int type = 0;
3347
3348 if (field_mask & BPF_SPIN_LOCK) {
3349 if (!strcmp(name, "bpf_spin_lock")) {
3350 if (*seen_mask & BPF_SPIN_LOCK)
3351 return -E2BIG;
3352 *seen_mask |= BPF_SPIN_LOCK;
3353 type = BPF_SPIN_LOCK;
3354 goto end;
3355 }
3356 }
3357 if (field_mask & BPF_TIMER) {
3358 if (!strcmp(name, "bpf_timer")) {
3359 if (*seen_mask & BPF_TIMER)
3360 return -E2BIG;
3361 *seen_mask |= BPF_TIMER;
3362 type = BPF_TIMER;
3363 goto end;
3364 }
3365 }
3366 if (field_mask & BPF_LIST_HEAD) {
3367 if (!strcmp(name, "bpf_list_head")) {
3368 type = BPF_LIST_HEAD;
3369 goto end;
3370 }
3371 }
3372 if (field_mask & BPF_LIST_NODE) {
3373 if (!strcmp(name, "bpf_list_node")) {
3374 type = BPF_LIST_NODE;
3375 goto end;
3376 }
3377 }
3378 /* Only return BPF_KPTR when all other types with matchable names fail */
3379 if (field_mask & BPF_KPTR) {
3380 type = BPF_KPTR_REF;
3381 goto end;
3382 }
3383 return 0;
3384end:
3385 *sz = btf_field_type_size(type);
3386 *align = btf_field_type_align(type);
3387 return type;
3388}
3389
3390static int btf_find_struct_field(const struct btf *btf,
3391 const struct btf_type *t, u32 field_mask,
3392 struct btf_field_info *info, int info_cnt)
3393{
3394 int ret, idx = 0, align, sz, field_type;
3395 const struct btf_member *member;
3396 struct btf_field_info tmp;
3397 u32 i, off, seen_mask = 0;
3398
3399 for_each_member(i, t, member) {
3400 const struct btf_type *member_type = btf_type_by_id(btf,
3401 member->type);
3402
3403 field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),
3404 field_mask, &seen_mask, &align, &sz);
3405 if (field_type == 0)
3406 continue;
3407 if (field_type < 0)
3408 return field_type;
3409
3410 off = __btf_member_bit_offset(t, member);
3411 if (off % 8)
3412 /* valid C code cannot generate such BTF */
3413 return -EINVAL;
3414 off /= 8;
3415 if (off % align)
3416 continue;
3417
3418 switch (field_type) {
3419 case BPF_SPIN_LOCK:
3420 case BPF_TIMER:
3421 case BPF_LIST_NODE:
3422 ret = btf_find_struct(btf, member_type, off, sz, field_type,
3423 idx < info_cnt ? &info[idx] : &tmp);
3424 if (ret < 0)
3425 return ret;
3426 break;
3427 case BPF_KPTR_UNREF:
3428 case BPF_KPTR_REF:
3429 ret = btf_find_kptr(btf, member_type, off, sz,
3430 idx < info_cnt ? &info[idx] : &tmp);
3431 if (ret < 0)
3432 return ret;
3433 break;
3434 case BPF_LIST_HEAD:
3435 ret = btf_find_list_head(btf, t, member_type, i, off, sz,
3436 idx < info_cnt ? &info[idx] : &tmp);
3437 if (ret < 0)
3438 return ret;
3439 break;
3440 default:
3441 return -EFAULT;
3442 }
3443
3444 if (ret == BTF_FIELD_IGNORE)
3445 continue;
3446 if (idx >= info_cnt)
3447 return -E2BIG;
3448 ++idx;
3449 }
3450 return idx;
3451}
3452
3453static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3454 u32 field_mask, struct btf_field_info *info,
3455 int info_cnt)
3456{
3457 int ret, idx = 0, align, sz, field_type;
3458 const struct btf_var_secinfo *vsi;
3459 struct btf_field_info tmp;
3460 u32 i, off, seen_mask = 0;
3461
3462 for_each_vsi(i, t, vsi) {
3463 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3464 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3465
3466 field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
3467 field_mask, &seen_mask, &align, &sz);
3468 if (field_type == 0)
3469 continue;
3470 if (field_type < 0)
3471 return field_type;
3472
3473 off = vsi->offset;
3474 if (vsi->size != sz)
3475 continue;
3476 if (off % align)
3477 continue;
3478
3479 switch (field_type) {
3480 case BPF_SPIN_LOCK:
3481 case BPF_TIMER:
3482 case BPF_LIST_NODE:
3483 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3484 idx < info_cnt ? &info[idx] : &tmp);
3485 if (ret < 0)
3486 return ret;
3487 break;
3488 case BPF_KPTR_UNREF:
3489 case BPF_KPTR_REF:
3490 ret = btf_find_kptr(btf, var_type, off, sz,
3491 idx < info_cnt ? &info[idx] : &tmp);
3492 if (ret < 0)
3493 return ret;
3494 break;
3495 case BPF_LIST_HEAD:
3496 ret = btf_find_list_head(btf, var, var_type, -1, off, sz,
3497 idx < info_cnt ? &info[idx] : &tmp);
3498 if (ret < 0)
3499 return ret;
3500 break;
3501 default:
3502 return -EFAULT;
3503 }
3504
3505 if (ret == BTF_FIELD_IGNORE)
3506 continue;
3507 if (idx >= info_cnt)
3508 return -E2BIG;
3509 ++idx;
3510 }
3511 return idx;
3512}
3513
3514static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3515 u32 field_mask, struct btf_field_info *info,
3516 int info_cnt)
3517{
3518 if (__btf_type_is_struct(t))
3519 return btf_find_struct_field(btf, t, field_mask, info, info_cnt);
3520 else if (btf_type_is_datasec(t))
3521 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt);
3522 return -EINVAL;
3523}
3524
3525static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3526 struct btf_field_info *info)
3527{
3528 struct module *mod = NULL;
3529 const struct btf_type *t;
3530 struct btf *kernel_btf;
3531 int ret;
3532 s32 id;
3533
3534 /* Find type in map BTF, and use it to look up the matching type
3535 * in vmlinux or module BTFs, by name and kind.
3536 */
3537 t = btf_type_by_id(btf, info->kptr.type_id);
3538 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3539 &kernel_btf);
3540 if (id < 0)
3541 return id;
3542
3543 /* Find and stash the function pointer for the destruction function that
3544 * needs to be eventually invoked from the map free path.
3545 */
3546 if (info->type == BPF_KPTR_REF) {
3547 const struct btf_type *dtor_func;
3548 const char *dtor_func_name;
3549 unsigned long addr;
3550 s32 dtor_btf_id;
3551
3552 /* This call also serves as a whitelist of allowed objects that
3553 * can be used as a referenced pointer and be stored in a map at
3554 * the same time.
3555 */
3556 dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id);
3557 if (dtor_btf_id < 0) {
3558 ret = dtor_btf_id;
3559 goto end_btf;
3560 }
3561
3562 dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id);
3563 if (!dtor_func) {
3564 ret = -ENOENT;
3565 goto end_btf;
3566 }
3567
3568 if (btf_is_module(kernel_btf)) {
3569 mod = btf_try_get_module(kernel_btf);
3570 if (!mod) {
3571 ret = -ENXIO;
3572 goto end_btf;
3573 }
3574 }
3575
3576 /* We already verified dtor_func to be btf_type_is_func
3577 * in register_btf_id_dtor_kfuncs.
3578 */
3579 dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off);
3580 addr = kallsyms_lookup_name(dtor_func_name);
3581 if (!addr) {
3582 ret = -EINVAL;
3583 goto end_mod;
3584 }
3585 field->kptr.dtor = (void *)addr;
3586 }
3587
3588 field->kptr.btf_id = id;
3589 field->kptr.btf = kernel_btf;
3590 field->kptr.module = mod;
3591 return 0;
3592end_mod:
3593 module_put(mod);
3594end_btf:
3595 btf_put(kernel_btf);
3596 return ret;
3597}
3598
3599static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3600 struct btf_field_info *info)
3601{
3602 const struct btf_type *t, *n = NULL;
3603 const struct btf_member *member;
3604 u32 offset;
3605 int i;
3606
3607 t = btf_type_by_id(btf, info->list_head.value_btf_id);
3608 /* We've already checked that value_btf_id is a struct type. We
3609 * just need to figure out the offset of the list_node, and
3610 * verify its type.
3611 */
3612 for_each_member(i, t, member) {
3613 if (strcmp(info->list_head.node_name, __btf_name_by_offset(btf, member->name_off)))
3614 continue;
3615 /* Invalid BTF, two members with same name */
3616 if (n)
3617 return -EINVAL;
3618 n = btf_type_by_id(btf, member->type);
3619 if (!__btf_type_is_struct(n))
3620 return -EINVAL;
3621 if (strcmp("bpf_list_node", __btf_name_by_offset(btf, n->name_off)))
3622 return -EINVAL;
3623 offset = __btf_member_bit_offset(n, member);
3624 if (offset % 8)
3625 return -EINVAL;
3626 offset /= 8;
3627 if (offset % __alignof__(struct bpf_list_node))
3628 return -EINVAL;
3629
3630 field->list_head.btf = (struct btf *)btf;
3631 field->list_head.value_btf_id = info->list_head.value_btf_id;
3632 field->list_head.node_offset = offset;
3633 }
3634 if (!n)
3635 return -ENOENT;
3636 return 0;
3637}
3638
3639struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3640 u32 field_mask, u32 value_size)
3641{
3642 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3643 struct btf_record *rec;
3644 u32 next_off = 0;
3645 int ret, i, cnt;
3646
3647 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3648 if (ret < 0)
3649 return ERR_PTR(ret);
3650 if (!ret)
3651 return NULL;
3652
3653 cnt = ret;
3654 /* This needs to be kzalloc to zero out padding and unused fields, see
3655 * comment in btf_record_equal.
3656 */
3657 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3658 if (!rec)
3659 return ERR_PTR(-ENOMEM);
3660
3661 rec->spin_lock_off = -EINVAL;
3662 rec->timer_off = -EINVAL;
3663 for (i = 0; i < cnt; i++) {
3664 if (info_arr[i].off + btf_field_type_size(info_arr[i].type) > value_size) {
3665 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3666 ret = -EFAULT;
3667 goto end;
3668 }
3669 if (info_arr[i].off < next_off) {
3670 ret = -EEXIST;
3671 goto end;
3672 }
3673 next_off = info_arr[i].off + btf_field_type_size(info_arr[i].type);
3674
3675 rec->field_mask |= info_arr[i].type;
3676 rec->fields[i].offset = info_arr[i].off;
3677 rec->fields[i].type = info_arr[i].type;
3678
3679 switch (info_arr[i].type) {
3680 case BPF_SPIN_LOCK:
3681 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3682 /* Cache offset for faster lookup at runtime */
3683 rec->spin_lock_off = rec->fields[i].offset;
3684 break;
3685 case BPF_TIMER:
3686 WARN_ON_ONCE(rec->timer_off >= 0);
3687 /* Cache offset for faster lookup at runtime */
3688 rec->timer_off = rec->fields[i].offset;
3689 break;
3690 case BPF_KPTR_UNREF:
3691 case BPF_KPTR_REF:
3692 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3693 if (ret < 0)
3694 goto end;
3695 break;
3696 case BPF_LIST_HEAD:
3697 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3698 if (ret < 0)
3699 goto end;
3700 break;
3701 case BPF_LIST_NODE:
3702 break;
3703 default:
3704 ret = -EFAULT;
3705 goto end;
3706 }
3707 rec->cnt++;
3708 }
3709
3710 /* bpf_list_head requires bpf_spin_lock */
3711 if (btf_record_has_field(rec, BPF_LIST_HEAD) && rec->spin_lock_off < 0) {
3712 ret = -EINVAL;
3713 goto end;
3714 }
3715
3716 return rec;
3717end:
3718 btf_record_free(rec);
3719 return ERR_PTR(ret);
3720}
3721
3722int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
3723{
3724 int i;
3725
3726 /* There are two owning types, kptr_ref and bpf_list_head. The former
3727 * only supports storing kernel types, which can never store references
3728 * to program allocated local types, atleast not yet. Hence we only need
3729 * to ensure that bpf_list_head ownership does not form cycles.
3730 */
3731 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_LIST_HEAD))
3732 return 0;
3733 for (i = 0; i < rec->cnt; i++) {
3734 struct btf_struct_meta *meta;
3735 u32 btf_id;
3736
3737 if (!(rec->fields[i].type & BPF_LIST_HEAD))
3738 continue;
3739 btf_id = rec->fields[i].list_head.value_btf_id;
3740 meta = btf_find_struct_meta(btf, btf_id);
3741 if (!meta)
3742 return -EFAULT;
3743 rec->fields[i].list_head.value_rec = meta->record;
3744
3745 if (!(rec->field_mask & BPF_LIST_NODE))
3746 continue;
3747
3748 /* We need to ensure ownership acyclicity among all types. The
3749 * proper way to do it would be to topologically sort all BTF
3750 * IDs based on the ownership edges, since there can be multiple
3751 * bpf_list_head in a type. Instead, we use the following
3752 * reasoning:
3753 *
3754 * - A type can only be owned by another type in user BTF if it
3755 * has a bpf_list_node.
3756 * - A type can only _own_ another type in user BTF if it has a
3757 * bpf_list_head.
3758 *
3759 * We ensure that if a type has both bpf_list_head and
3760 * bpf_list_node, its element types cannot be owning types.
3761 *
3762 * To ensure acyclicity:
3763 *
3764 * When A only has bpf_list_head, ownership chain can be:
3765 * A -> B -> C
3766 * Where:
3767 * - B has both bpf_list_head and bpf_list_node.
3768 * - C only has bpf_list_node.
3769 *
3770 * When A has both bpf_list_head and bpf_list_node, some other
3771 * type already owns it in the BTF domain, hence it can not own
3772 * another owning type through any of the bpf_list_head edges.
3773 * A -> B
3774 * Where:
3775 * - B only has bpf_list_node.
3776 */
3777 if (meta->record->field_mask & BPF_LIST_HEAD)
3778 return -ELOOP;
3779 }
3780 return 0;
3781}
3782
3783static int btf_field_offs_cmp(const void *_a, const void *_b, const void *priv)
3784{
3785 const u32 a = *(const u32 *)_a;
3786 const u32 b = *(const u32 *)_b;
3787
3788 if (a < b)
3789 return -1;
3790 else if (a > b)
3791 return 1;
3792 return 0;
3793}
3794
3795static void btf_field_offs_swap(void *_a, void *_b, int size, const void *priv)
3796{
3797 struct btf_field_offs *foffs = (void *)priv;
3798 u32 *off_base = foffs->field_off;
3799 u32 *a = _a, *b = _b;
3800 u8 *sz_a, *sz_b;
3801
3802 sz_a = foffs->field_sz + (a - off_base);
3803 sz_b = foffs->field_sz + (b - off_base);
3804
3805 swap(*a, *b);
3806 swap(*sz_a, *sz_b);
3807}
3808
3809struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec)
3810{
3811 struct btf_field_offs *foffs;
3812 u32 i, *off;
3813 u8 *sz;
3814
3815 BUILD_BUG_ON(ARRAY_SIZE(foffs->field_off) != ARRAY_SIZE(foffs->field_sz));
3816 if (IS_ERR_OR_NULL(rec))
3817 return NULL;
3818
3819 foffs = kzalloc(sizeof(*foffs), GFP_KERNEL | __GFP_NOWARN);
3820 if (!foffs)
3821 return ERR_PTR(-ENOMEM);
3822
3823 off = foffs->field_off;
3824 sz = foffs->field_sz;
3825 for (i = 0; i < rec->cnt; i++) {
3826 off[i] = rec->fields[i].offset;
3827 sz[i] = btf_field_type_size(rec->fields[i].type);
3828 }
3829 foffs->cnt = rec->cnt;
3830
3831 if (foffs->cnt == 1)
3832 return foffs;
3833 sort_r(foffs->field_off, foffs->cnt, sizeof(foffs->field_off[0]),
3834 btf_field_offs_cmp, btf_field_offs_swap, foffs);
3835 return foffs;
3836}
3837
3838static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3839 u32 type_id, void *data, u8 bits_offset,
3840 struct btf_show *show)
3841{
3842 const struct btf_member *member;
3843 void *safe_data;
3844 u32 i;
3845
3846 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3847 if (!safe_data)
3848 return;
3849
3850 for_each_member(i, t, member) {
3851 const struct btf_type *member_type = btf_type_by_id(btf,
3852 member->type);
3853 const struct btf_kind_operations *ops;
3854 u32 member_offset, bitfield_size;
3855 u32 bytes_offset;
3856 u8 bits8_offset;
3857
3858 btf_show_start_member(show, member);
3859
3860 member_offset = __btf_member_bit_offset(t, member);
3861 bitfield_size = __btf_member_bitfield_size(t, member);
3862 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3863 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3864 if (bitfield_size) {
3865 safe_data = btf_show_start_type(show, member_type,
3866 member->type,
3867 data + bytes_offset);
3868 if (safe_data)
3869 btf_bitfield_show(safe_data,
3870 bits8_offset,
3871 bitfield_size, show);
3872 btf_show_end_type(show);
3873 } else {
3874 ops = btf_type_ops(member_type);
3875 ops->show(btf, member_type, member->type,
3876 data + bytes_offset, bits8_offset, show);
3877 }
3878
3879 btf_show_end_member(show);
3880 }
3881
3882 btf_show_end_struct_type(show);
3883}
3884
3885static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3886 u32 type_id, void *data, u8 bits_offset,
3887 struct btf_show *show)
3888{
3889 const struct btf_member *m = show->state.member;
3890
3891 /*
3892 * First check if any members would be shown (are non-zero).
3893 * See comments above "struct btf_show" definition for more
3894 * details on how this works at a high-level.
3895 */
3896 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3897 if (!show->state.depth_check) {
3898 show->state.depth_check = show->state.depth + 1;
3899 show->state.depth_to_show = 0;
3900 }
3901 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3902 /* Restore saved member data here */
3903 show->state.member = m;
3904 if (show->state.depth_check != show->state.depth + 1)
3905 return;
3906 show->state.depth_check = 0;
3907
3908 if (show->state.depth_to_show <= show->state.depth)
3909 return;
3910 /*
3911 * Reaching here indicates we have recursed and found
3912 * non-zero child values.
3913 */
3914 }
3915
3916 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3917}
3918
3919static struct btf_kind_operations struct_ops = {
3920 .check_meta = btf_struct_check_meta,
3921 .resolve = btf_struct_resolve,
3922 .check_member = btf_struct_check_member,
3923 .check_kflag_member = btf_generic_check_kflag_member,
3924 .log_details = btf_struct_log,
3925 .show = btf_struct_show,
3926};
3927
3928static int btf_enum_check_member(struct btf_verifier_env *env,
3929 const struct btf_type *struct_type,
3930 const struct btf_member *member,
3931 const struct btf_type *member_type)
3932{
3933 u32 struct_bits_off = member->offset;
3934 u32 struct_size, bytes_offset;
3935
3936 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3937 btf_verifier_log_member(env, struct_type, member,
3938 "Member is not byte aligned");
3939 return -EINVAL;
3940 }
3941
3942 struct_size = struct_type->size;
3943 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3944 if (struct_size - bytes_offset < member_type->size) {
3945 btf_verifier_log_member(env, struct_type, member,
3946 "Member exceeds struct_size");
3947 return -EINVAL;
3948 }
3949
3950 return 0;
3951}
3952
3953static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3954 const struct btf_type *struct_type,
3955 const struct btf_member *member,
3956 const struct btf_type *member_type)
3957{
3958 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3959 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3960
3961 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3962 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3963 if (!nr_bits) {
3964 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3965 btf_verifier_log_member(env, struct_type, member,
3966 "Member is not byte aligned");
3967 return -EINVAL;
3968 }
3969
3970 nr_bits = int_bitsize;
3971 } else if (nr_bits > int_bitsize) {
3972 btf_verifier_log_member(env, struct_type, member,
3973 "Invalid member bitfield_size");
3974 return -EINVAL;
3975 }
3976
3977 struct_size = struct_type->size;
3978 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3979 if (struct_size < bytes_end) {
3980 btf_verifier_log_member(env, struct_type, member,
3981 "Member exceeds struct_size");
3982 return -EINVAL;
3983 }
3984
3985 return 0;
3986}
3987
3988static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3989 const struct btf_type *t,
3990 u32 meta_left)
3991{
3992 const struct btf_enum *enums = btf_type_enum(t);
3993 struct btf *btf = env->btf;
3994 const char *fmt_str;
3995 u16 i, nr_enums;
3996 u32 meta_needed;
3997
3998 nr_enums = btf_type_vlen(t);
3999 meta_needed = nr_enums * sizeof(*enums);
4000
4001 if (meta_left < meta_needed) {
4002 btf_verifier_log_basic(env, t,
4003 "meta_left:%u meta_needed:%u",
4004 meta_left, meta_needed);
4005 return -EINVAL;
4006 }
4007
4008 if (t->size > 8 || !is_power_of_2(t->size)) {
4009 btf_verifier_log_type(env, t, "Unexpected size");
4010 return -EINVAL;
4011 }
4012
4013 /* enum type either no name or a valid one */
4014 if (t->name_off &&
4015 !btf_name_valid_identifier(env->btf, t->name_off)) {
4016 btf_verifier_log_type(env, t, "Invalid name");
4017 return -EINVAL;
4018 }
4019
4020 btf_verifier_log_type(env, t, NULL);
4021
4022 for (i = 0; i < nr_enums; i++) {
4023 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4024 btf_verifier_log(env, "\tInvalid name_offset:%u",
4025 enums[i].name_off);
4026 return -EINVAL;
4027 }
4028
4029 /* enum member must have a valid name */
4030 if (!enums[i].name_off ||
4031 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4032 btf_verifier_log_type(env, t, "Invalid name");
4033 return -EINVAL;
4034 }
4035
4036 if (env->log.level == BPF_LOG_KERNEL)
4037 continue;
4038 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4039 btf_verifier_log(env, fmt_str,
4040 __btf_name_by_offset(btf, enums[i].name_off),
4041 enums[i].val);
4042 }
4043
4044 return meta_needed;
4045}
4046
4047static void btf_enum_log(struct btf_verifier_env *env,
4048 const struct btf_type *t)
4049{
4050 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4051}
4052
4053static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4054 u32 type_id, void *data, u8 bits_offset,
4055 struct btf_show *show)
4056{
4057 const struct btf_enum *enums = btf_type_enum(t);
4058 u32 i, nr_enums = btf_type_vlen(t);
4059 void *safe_data;
4060 int v;
4061
4062 safe_data = btf_show_start_type(show, t, type_id, data);
4063 if (!safe_data)
4064 return;
4065
4066 v = *(int *)safe_data;
4067
4068 for (i = 0; i < nr_enums; i++) {
4069 if (v != enums[i].val)
4070 continue;
4071
4072 btf_show_type_value(show, "%s",
4073 __btf_name_by_offset(btf,
4074 enums[i].name_off));
4075
4076 btf_show_end_type(show);
4077 return;
4078 }
4079
4080 if (btf_type_kflag(t))
4081 btf_show_type_value(show, "%d", v);
4082 else
4083 btf_show_type_value(show, "%u", v);
4084 btf_show_end_type(show);
4085}
4086
4087static struct btf_kind_operations enum_ops = {
4088 .check_meta = btf_enum_check_meta,
4089 .resolve = btf_df_resolve,
4090 .check_member = btf_enum_check_member,
4091 .check_kflag_member = btf_enum_check_kflag_member,
4092 .log_details = btf_enum_log,
4093 .show = btf_enum_show,
4094};
4095
4096static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4097 const struct btf_type *t,
4098 u32 meta_left)
4099{
4100 const struct btf_enum64 *enums = btf_type_enum64(t);
4101 struct btf *btf = env->btf;
4102 const char *fmt_str;
4103 u16 i, nr_enums;
4104 u32 meta_needed;
4105
4106 nr_enums = btf_type_vlen(t);
4107 meta_needed = nr_enums * sizeof(*enums);
4108
4109 if (meta_left < meta_needed) {
4110 btf_verifier_log_basic(env, t,
4111 "meta_left:%u meta_needed:%u",
4112 meta_left, meta_needed);
4113 return -EINVAL;
4114 }
4115
4116 if (t->size > 8 || !is_power_of_2(t->size)) {
4117 btf_verifier_log_type(env, t, "Unexpected size");
4118 return -EINVAL;
4119 }
4120
4121 /* enum type either no name or a valid one */
4122 if (t->name_off &&
4123 !btf_name_valid_identifier(env->btf, t->name_off)) {
4124 btf_verifier_log_type(env, t, "Invalid name");
4125 return -EINVAL;
4126 }
4127
4128 btf_verifier_log_type(env, t, NULL);
4129
4130 for (i = 0; i < nr_enums; i++) {
4131 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4132 btf_verifier_log(env, "\tInvalid name_offset:%u",
4133 enums[i].name_off);
4134 return -EINVAL;
4135 }
4136
4137 /* enum member must have a valid name */
4138 if (!enums[i].name_off ||
4139 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4140 btf_verifier_log_type(env, t, "Invalid name");
4141 return -EINVAL;
4142 }
4143
4144 if (env->log.level == BPF_LOG_KERNEL)
4145 continue;
4146
4147 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4148 btf_verifier_log(env, fmt_str,
4149 __btf_name_by_offset(btf, enums[i].name_off),
4150 btf_enum64_value(enums + i));
4151 }
4152
4153 return meta_needed;
4154}
4155
4156static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4157 u32 type_id, void *data, u8 bits_offset,
4158 struct btf_show *show)
4159{
4160 const struct btf_enum64 *enums = btf_type_enum64(t);
4161 u32 i, nr_enums = btf_type_vlen(t);
4162 void *safe_data;
4163 s64 v;
4164
4165 safe_data = btf_show_start_type(show, t, type_id, data);
4166 if (!safe_data)
4167 return;
4168
4169 v = *(u64 *)safe_data;
4170
4171 for (i = 0; i < nr_enums; i++) {
4172 if (v != btf_enum64_value(enums + i))
4173 continue;
4174
4175 btf_show_type_value(show, "%s",
4176 __btf_name_by_offset(btf,
4177 enums[i].name_off));
4178
4179 btf_show_end_type(show);
4180 return;
4181 }
4182
4183 if (btf_type_kflag(t))
4184 btf_show_type_value(show, "%lld", v);
4185 else
4186 btf_show_type_value(show, "%llu", v);
4187 btf_show_end_type(show);
4188}
4189
4190static struct btf_kind_operations enum64_ops = {
4191 .check_meta = btf_enum64_check_meta,
4192 .resolve = btf_df_resolve,
4193 .check_member = btf_enum_check_member,
4194 .check_kflag_member = btf_enum_check_kflag_member,
4195 .log_details = btf_enum_log,
4196 .show = btf_enum64_show,
4197};
4198
4199static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4200 const struct btf_type *t,
4201 u32 meta_left)
4202{
4203 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4204
4205 if (meta_left < meta_needed) {
4206 btf_verifier_log_basic(env, t,
4207 "meta_left:%u meta_needed:%u",
4208 meta_left, meta_needed);
4209 return -EINVAL;
4210 }
4211
4212 if (t->name_off) {
4213 btf_verifier_log_type(env, t, "Invalid name");
4214 return -EINVAL;
4215 }
4216
4217 if (btf_type_kflag(t)) {
4218 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4219 return -EINVAL;
4220 }
4221
4222 btf_verifier_log_type(env, t, NULL);
4223
4224 return meta_needed;
4225}
4226
4227static void btf_func_proto_log(struct btf_verifier_env *env,
4228 const struct btf_type *t)
4229{
4230 const struct btf_param *args = (const struct btf_param *)(t + 1);
4231 u16 nr_args = btf_type_vlen(t), i;
4232
4233 btf_verifier_log(env, "return=%u args=(", t->type);
4234 if (!nr_args) {
4235 btf_verifier_log(env, "void");
4236 goto done;
4237 }
4238
4239 if (nr_args == 1 && !args[0].type) {
4240 /* Only one vararg */
4241 btf_verifier_log(env, "vararg");
4242 goto done;
4243 }
4244
4245 btf_verifier_log(env, "%u %s", args[0].type,
4246 __btf_name_by_offset(env->btf,
4247 args[0].name_off));
4248 for (i = 1; i < nr_args - 1; i++)
4249 btf_verifier_log(env, ", %u %s", args[i].type,
4250 __btf_name_by_offset(env->btf,
4251 args[i].name_off));
4252
4253 if (nr_args > 1) {
4254 const struct btf_param *last_arg = &args[nr_args - 1];
4255
4256 if (last_arg->type)
4257 btf_verifier_log(env, ", %u %s", last_arg->type,
4258 __btf_name_by_offset(env->btf,
4259 last_arg->name_off));
4260 else
4261 btf_verifier_log(env, ", vararg");
4262 }
4263
4264done:
4265 btf_verifier_log(env, ")");
4266}
4267
4268static struct btf_kind_operations func_proto_ops = {
4269 .check_meta = btf_func_proto_check_meta,
4270 .resolve = btf_df_resolve,
4271 /*
4272 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4273 * a struct's member.
4274 *
4275 * It should be a function pointer instead.
4276 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4277 *
4278 * Hence, there is no btf_func_check_member().
4279 */
4280 .check_member = btf_df_check_member,
4281 .check_kflag_member = btf_df_check_kflag_member,
4282 .log_details = btf_func_proto_log,
4283 .show = btf_df_show,
4284};
4285
4286static s32 btf_func_check_meta(struct btf_verifier_env *env,
4287 const struct btf_type *t,
4288 u32 meta_left)
4289{
4290 if (!t->name_off ||
4291 !btf_name_valid_identifier(env->btf, t->name_off)) {
4292 btf_verifier_log_type(env, t, "Invalid name");
4293 return -EINVAL;
4294 }
4295
4296 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4297 btf_verifier_log_type(env, t, "Invalid func linkage");
4298 return -EINVAL;
4299 }
4300
4301 if (btf_type_kflag(t)) {
4302 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4303 return -EINVAL;
4304 }
4305
4306 btf_verifier_log_type(env, t, NULL);
4307
4308 return 0;
4309}
4310
4311static int btf_func_resolve(struct btf_verifier_env *env,
4312 const struct resolve_vertex *v)
4313{
4314 const struct btf_type *t = v->t;
4315 u32 next_type_id = t->type;
4316 int err;
4317
4318 err = btf_func_check(env, t);
4319 if (err)
4320 return err;
4321
4322 env_stack_pop_resolved(env, next_type_id, 0);
4323 return 0;
4324}
4325
4326static struct btf_kind_operations func_ops = {
4327 .check_meta = btf_func_check_meta,
4328 .resolve = btf_func_resolve,
4329 .check_member = btf_df_check_member,
4330 .check_kflag_member = btf_df_check_kflag_member,
4331 .log_details = btf_ref_type_log,
4332 .show = btf_df_show,
4333};
4334
4335static s32 btf_var_check_meta(struct btf_verifier_env *env,
4336 const struct btf_type *t,
4337 u32 meta_left)
4338{
4339 const struct btf_var *var;
4340 u32 meta_needed = sizeof(*var);
4341
4342 if (meta_left < meta_needed) {
4343 btf_verifier_log_basic(env, t,
4344 "meta_left:%u meta_needed:%u",
4345 meta_left, meta_needed);
4346 return -EINVAL;
4347 }
4348
4349 if (btf_type_vlen(t)) {
4350 btf_verifier_log_type(env, t, "vlen != 0");
4351 return -EINVAL;
4352 }
4353
4354 if (btf_type_kflag(t)) {
4355 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4356 return -EINVAL;
4357 }
4358
4359 if (!t->name_off ||
4360 !__btf_name_valid(env->btf, t->name_off, true)) {
4361 btf_verifier_log_type(env, t, "Invalid name");
4362 return -EINVAL;
4363 }
4364
4365 /* A var cannot be in type void */
4366 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4367 btf_verifier_log_type(env, t, "Invalid type_id");
4368 return -EINVAL;
4369 }
4370
4371 var = btf_type_var(t);
4372 if (var->linkage != BTF_VAR_STATIC &&
4373 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4374 btf_verifier_log_type(env, t, "Linkage not supported");
4375 return -EINVAL;
4376 }
4377
4378 btf_verifier_log_type(env, t, NULL);
4379
4380 return meta_needed;
4381}
4382
4383static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4384{
4385 const struct btf_var *var = btf_type_var(t);
4386
4387 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4388}
4389
4390static const struct btf_kind_operations var_ops = {
4391 .check_meta = btf_var_check_meta,
4392 .resolve = btf_var_resolve,
4393 .check_member = btf_df_check_member,
4394 .check_kflag_member = btf_df_check_kflag_member,
4395 .log_details = btf_var_log,
4396 .show = btf_var_show,
4397};
4398
4399static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4400 const struct btf_type *t,
4401 u32 meta_left)
4402{
4403 const struct btf_var_secinfo *vsi;
4404 u64 last_vsi_end_off = 0, sum = 0;
4405 u32 i, meta_needed;
4406
4407 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4408 if (meta_left < meta_needed) {
4409 btf_verifier_log_basic(env, t,
4410 "meta_left:%u meta_needed:%u",
4411 meta_left, meta_needed);
4412 return -EINVAL;
4413 }
4414
4415 if (!t->size) {
4416 btf_verifier_log_type(env, t, "size == 0");
4417 return -EINVAL;
4418 }
4419
4420 if (btf_type_kflag(t)) {
4421 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4422 return -EINVAL;
4423 }
4424
4425 if (!t->name_off ||
4426 !btf_name_valid_section(env->btf, t->name_off)) {
4427 btf_verifier_log_type(env, t, "Invalid name");
4428 return -EINVAL;
4429 }
4430
4431 btf_verifier_log_type(env, t, NULL);
4432
4433 for_each_vsi(i, t, vsi) {
4434 /* A var cannot be in type void */
4435 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4436 btf_verifier_log_vsi(env, t, vsi,
4437 "Invalid type_id");
4438 return -EINVAL;
4439 }
4440
4441 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4442 btf_verifier_log_vsi(env, t, vsi,
4443 "Invalid offset");
4444 return -EINVAL;
4445 }
4446
4447 if (!vsi->size || vsi->size > t->size) {
4448 btf_verifier_log_vsi(env, t, vsi,
4449 "Invalid size");
4450 return -EINVAL;
4451 }
4452
4453 last_vsi_end_off = vsi->offset + vsi->size;
4454 if (last_vsi_end_off > t->size) {
4455 btf_verifier_log_vsi(env, t, vsi,
4456 "Invalid offset+size");
4457 return -EINVAL;
4458 }
4459
4460 btf_verifier_log_vsi(env, t, vsi, NULL);
4461 sum += vsi->size;
4462 }
4463
4464 if (t->size < sum) {
4465 btf_verifier_log_type(env, t, "Invalid btf_info size");
4466 return -EINVAL;
4467 }
4468
4469 return meta_needed;
4470}
4471
4472static int btf_datasec_resolve(struct btf_verifier_env *env,
4473 const struct resolve_vertex *v)
4474{
4475 const struct btf_var_secinfo *vsi;
4476 struct btf *btf = env->btf;
4477 u16 i;
4478
4479 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4480 u32 var_type_id = vsi->type, type_id, type_size = 0;
4481 const struct btf_type *var_type = btf_type_by_id(env->btf,
4482 var_type_id);
4483 if (!var_type || !btf_type_is_var(var_type)) {
4484 btf_verifier_log_vsi(env, v->t, vsi,
4485 "Not a VAR kind member");
4486 return -EINVAL;
4487 }
4488
4489 if (!env_type_is_resolve_sink(env, var_type) &&
4490 !env_type_is_resolved(env, var_type_id)) {
4491 env_stack_set_next_member(env, i + 1);
4492 return env_stack_push(env, var_type, var_type_id);
4493 }
4494
4495 type_id = var_type->type;
4496 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4497 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4498 return -EINVAL;
4499 }
4500
4501 if (vsi->size < type_size) {
4502 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4503 return -EINVAL;
4504 }
4505 }
4506
4507 env_stack_pop_resolved(env, 0, 0);
4508 return 0;
4509}
4510
4511static void btf_datasec_log(struct btf_verifier_env *env,
4512 const struct btf_type *t)
4513{
4514 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4515}
4516
4517static void btf_datasec_show(const struct btf *btf,
4518 const struct btf_type *t, u32 type_id,
4519 void *data, u8 bits_offset,
4520 struct btf_show *show)
4521{
4522 const struct btf_var_secinfo *vsi;
4523 const struct btf_type *var;
4524 u32 i;
4525
4526 if (!btf_show_start_type(show, t, type_id, data))
4527 return;
4528
4529 btf_show_type_value(show, "section (\"%s\") = {",
4530 __btf_name_by_offset(btf, t->name_off));
4531 for_each_vsi(i, t, vsi) {
4532 var = btf_type_by_id(btf, vsi->type);
4533 if (i)
4534 btf_show(show, ",");
4535 btf_type_ops(var)->show(btf, var, vsi->type,
4536 data + vsi->offset, bits_offset, show);
4537 }
4538 btf_show_end_type(show);
4539}
4540
4541static const struct btf_kind_operations datasec_ops = {
4542 .check_meta = btf_datasec_check_meta,
4543 .resolve = btf_datasec_resolve,
4544 .check_member = btf_df_check_member,
4545 .check_kflag_member = btf_df_check_kflag_member,
4546 .log_details = btf_datasec_log,
4547 .show = btf_datasec_show,
4548};
4549
4550static s32 btf_float_check_meta(struct btf_verifier_env *env,
4551 const struct btf_type *t,
4552 u32 meta_left)
4553{
4554 if (btf_type_vlen(t)) {
4555 btf_verifier_log_type(env, t, "vlen != 0");
4556 return -EINVAL;
4557 }
4558
4559 if (btf_type_kflag(t)) {
4560 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4561 return -EINVAL;
4562 }
4563
4564 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4565 t->size != 16) {
4566 btf_verifier_log_type(env, t, "Invalid type_size");
4567 return -EINVAL;
4568 }
4569
4570 btf_verifier_log_type(env, t, NULL);
4571
4572 return 0;
4573}
4574
4575static int btf_float_check_member(struct btf_verifier_env *env,
4576 const struct btf_type *struct_type,
4577 const struct btf_member *member,
4578 const struct btf_type *member_type)
4579{
4580 u64 start_offset_bytes;
4581 u64 end_offset_bytes;
4582 u64 misalign_bits;
4583 u64 align_bytes;
4584 u64 align_bits;
4585
4586 /* Different architectures have different alignment requirements, so
4587 * here we check only for the reasonable minimum. This way we ensure
4588 * that types after CO-RE can pass the kernel BTF verifier.
4589 */
4590 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4591 align_bits = align_bytes * BITS_PER_BYTE;
4592 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4593 if (misalign_bits) {
4594 btf_verifier_log_member(env, struct_type, member,
4595 "Member is not properly aligned");
4596 return -EINVAL;
4597 }
4598
4599 start_offset_bytes = member->offset / BITS_PER_BYTE;
4600 end_offset_bytes = start_offset_bytes + member_type->size;
4601 if (end_offset_bytes > struct_type->size) {
4602 btf_verifier_log_member(env, struct_type, member,
4603 "Member exceeds struct_size");
4604 return -EINVAL;
4605 }
4606
4607 return 0;
4608}
4609
4610static void btf_float_log(struct btf_verifier_env *env,
4611 const struct btf_type *t)
4612{
4613 btf_verifier_log(env, "size=%u", t->size);
4614}
4615
4616static const struct btf_kind_operations float_ops = {
4617 .check_meta = btf_float_check_meta,
4618 .resolve = btf_df_resolve,
4619 .check_member = btf_float_check_member,
4620 .check_kflag_member = btf_generic_check_kflag_member,
4621 .log_details = btf_float_log,
4622 .show = btf_df_show,
4623};
4624
4625static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4626 const struct btf_type *t,
4627 u32 meta_left)
4628{
4629 const struct btf_decl_tag *tag;
4630 u32 meta_needed = sizeof(*tag);
4631 s32 component_idx;
4632 const char *value;
4633
4634 if (meta_left < meta_needed) {
4635 btf_verifier_log_basic(env, t,
4636 "meta_left:%u meta_needed:%u",
4637 meta_left, meta_needed);
4638 return -EINVAL;
4639 }
4640
4641 value = btf_name_by_offset(env->btf, t->name_off);
4642 if (!value || !value[0]) {
4643 btf_verifier_log_type(env, t, "Invalid value");
4644 return -EINVAL;
4645 }
4646
4647 if (btf_type_vlen(t)) {
4648 btf_verifier_log_type(env, t, "vlen != 0");
4649 return -EINVAL;
4650 }
4651
4652 if (btf_type_kflag(t)) {
4653 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4654 return -EINVAL;
4655 }
4656
4657 component_idx = btf_type_decl_tag(t)->component_idx;
4658 if (component_idx < -1) {
4659 btf_verifier_log_type(env, t, "Invalid component_idx");
4660 return -EINVAL;
4661 }
4662
4663 btf_verifier_log_type(env, t, NULL);
4664
4665 return meta_needed;
4666}
4667
4668static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4669 const struct resolve_vertex *v)
4670{
4671 const struct btf_type *next_type;
4672 const struct btf_type *t = v->t;
4673 u32 next_type_id = t->type;
4674 struct btf *btf = env->btf;
4675 s32 component_idx;
4676 u32 vlen;
4677
4678 next_type = btf_type_by_id(btf, next_type_id);
4679 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4680 btf_verifier_log_type(env, v->t, "Invalid type_id");
4681 return -EINVAL;
4682 }
4683
4684 if (!env_type_is_resolve_sink(env, next_type) &&
4685 !env_type_is_resolved(env, next_type_id))
4686 return env_stack_push(env, next_type, next_type_id);
4687
4688 component_idx = btf_type_decl_tag(t)->component_idx;
4689 if (component_idx != -1) {
4690 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4691 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4692 return -EINVAL;
4693 }
4694
4695 if (btf_type_is_struct(next_type)) {
4696 vlen = btf_type_vlen(next_type);
4697 } else {
4698 /* next_type should be a function */
4699 next_type = btf_type_by_id(btf, next_type->type);
4700 vlen = btf_type_vlen(next_type);
4701 }
4702
4703 if ((u32)component_idx >= vlen) {
4704 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4705 return -EINVAL;
4706 }
4707 }
4708
4709 env_stack_pop_resolved(env, next_type_id, 0);
4710
4711 return 0;
4712}
4713
4714static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4715{
4716 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4717 btf_type_decl_tag(t)->component_idx);
4718}
4719
4720static const struct btf_kind_operations decl_tag_ops = {
4721 .check_meta = btf_decl_tag_check_meta,
4722 .resolve = btf_decl_tag_resolve,
4723 .check_member = btf_df_check_member,
4724 .check_kflag_member = btf_df_check_kflag_member,
4725 .log_details = btf_decl_tag_log,
4726 .show = btf_df_show,
4727};
4728
4729static int btf_func_proto_check(struct btf_verifier_env *env,
4730 const struct btf_type *t)
4731{
4732 const struct btf_type *ret_type;
4733 const struct btf_param *args;
4734 const struct btf *btf;
4735 u16 nr_args, i;
4736 int err;
4737
4738 btf = env->btf;
4739 args = (const struct btf_param *)(t + 1);
4740 nr_args = btf_type_vlen(t);
4741
4742 /* Check func return type which could be "void" (t->type == 0) */
4743 if (t->type) {
4744 u32 ret_type_id = t->type;
4745
4746 ret_type = btf_type_by_id(btf, ret_type_id);
4747 if (!ret_type) {
4748 btf_verifier_log_type(env, t, "Invalid return type");
4749 return -EINVAL;
4750 }
4751
4752 if (btf_type_is_resolve_source_only(ret_type)) {
4753 btf_verifier_log_type(env, t, "Invalid return type");
4754 return -EINVAL;
4755 }
4756
4757 if (btf_type_needs_resolve(ret_type) &&
4758 !env_type_is_resolved(env, ret_type_id)) {
4759 err = btf_resolve(env, ret_type, ret_type_id);
4760 if (err)
4761 return err;
4762 }
4763
4764 /* Ensure the return type is a type that has a size */
4765 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4766 btf_verifier_log_type(env, t, "Invalid return type");
4767 return -EINVAL;
4768 }
4769 }
4770
4771 if (!nr_args)
4772 return 0;
4773
4774 /* Last func arg type_id could be 0 if it is a vararg */
4775 if (!args[nr_args - 1].type) {
4776 if (args[nr_args - 1].name_off) {
4777 btf_verifier_log_type(env, t, "Invalid arg#%u",
4778 nr_args);
4779 return -EINVAL;
4780 }
4781 nr_args--;
4782 }
4783
4784 for (i = 0; i < nr_args; i++) {
4785 const struct btf_type *arg_type;
4786 u32 arg_type_id;
4787
4788 arg_type_id = args[i].type;
4789 arg_type = btf_type_by_id(btf, arg_type_id);
4790 if (!arg_type) {
4791 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4792 return -EINVAL;
4793 }
4794
4795 if (btf_type_is_resolve_source_only(arg_type)) {
4796 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4797 return -EINVAL;
4798 }
4799
4800 if (args[i].name_off &&
4801 (!btf_name_offset_valid(btf, args[i].name_off) ||
4802 !btf_name_valid_identifier(btf, args[i].name_off))) {
4803 btf_verifier_log_type(env, t,
4804 "Invalid arg#%u", i + 1);
4805 return -EINVAL;
4806 }
4807
4808 if (btf_type_needs_resolve(arg_type) &&
4809 !env_type_is_resolved(env, arg_type_id)) {
4810 err = btf_resolve(env, arg_type, arg_type_id);
4811 if (err)
4812 return err;
4813 }
4814
4815 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4816 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4817 return -EINVAL;
4818 }
4819 }
4820
4821 return 0;
4822}
4823
4824static int btf_func_check(struct btf_verifier_env *env,
4825 const struct btf_type *t)
4826{
4827 const struct btf_type *proto_type;
4828 const struct btf_param *args;
4829 const struct btf *btf;
4830 u16 nr_args, i;
4831
4832 btf = env->btf;
4833 proto_type = btf_type_by_id(btf, t->type);
4834
4835 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4836 btf_verifier_log_type(env, t, "Invalid type_id");
4837 return -EINVAL;
4838 }
4839
4840 args = (const struct btf_param *)(proto_type + 1);
4841 nr_args = btf_type_vlen(proto_type);
4842 for (i = 0; i < nr_args; i++) {
4843 if (!args[i].name_off && args[i].type) {
4844 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4845 return -EINVAL;
4846 }
4847 }
4848
4849 return 0;
4850}
4851
4852static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4853 [BTF_KIND_INT] = &int_ops,
4854 [BTF_KIND_PTR] = &ptr_ops,
4855 [BTF_KIND_ARRAY] = &array_ops,
4856 [BTF_KIND_STRUCT] = &struct_ops,
4857 [BTF_KIND_UNION] = &struct_ops,
4858 [BTF_KIND_ENUM] = &enum_ops,
4859 [BTF_KIND_FWD] = &fwd_ops,
4860 [BTF_KIND_TYPEDEF] = &modifier_ops,
4861 [BTF_KIND_VOLATILE] = &modifier_ops,
4862 [BTF_KIND_CONST] = &modifier_ops,
4863 [BTF_KIND_RESTRICT] = &modifier_ops,
4864 [BTF_KIND_FUNC] = &func_ops,
4865 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4866 [BTF_KIND_VAR] = &var_ops,
4867 [BTF_KIND_DATASEC] = &datasec_ops,
4868 [BTF_KIND_FLOAT] = &float_ops,
4869 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4870 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4871 [BTF_KIND_ENUM64] = &enum64_ops,
4872};
4873
4874static s32 btf_check_meta(struct btf_verifier_env *env,
4875 const struct btf_type *t,
4876 u32 meta_left)
4877{
4878 u32 saved_meta_left = meta_left;
4879 s32 var_meta_size;
4880
4881 if (meta_left < sizeof(*t)) {
4882 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4883 env->log_type_id, meta_left, sizeof(*t));
4884 return -EINVAL;
4885 }
4886 meta_left -= sizeof(*t);
4887
4888 if (t->info & ~BTF_INFO_MASK) {
4889 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4890 env->log_type_id, t->info);
4891 return -EINVAL;
4892 }
4893
4894 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4895 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4896 btf_verifier_log(env, "[%u] Invalid kind:%u",
4897 env->log_type_id, BTF_INFO_KIND(t->info));
4898 return -EINVAL;
4899 }
4900
4901 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4902 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4903 env->log_type_id, t->name_off);
4904 return -EINVAL;
4905 }
4906
4907 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4908 if (var_meta_size < 0)
4909 return var_meta_size;
4910
4911 meta_left -= var_meta_size;
4912
4913 return saved_meta_left - meta_left;
4914}
4915
4916static int btf_check_all_metas(struct btf_verifier_env *env)
4917{
4918 struct btf *btf = env->btf;
4919 struct btf_header *hdr;
4920 void *cur, *end;
4921
4922 hdr = &btf->hdr;
4923 cur = btf->nohdr_data + hdr->type_off;
4924 end = cur + hdr->type_len;
4925
4926 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4927 while (cur < end) {
4928 struct btf_type *t = cur;
4929 s32 meta_size;
4930
4931 meta_size = btf_check_meta(env, t, end - cur);
4932 if (meta_size < 0)
4933 return meta_size;
4934
4935 btf_add_type(env, t);
4936 cur += meta_size;
4937 env->log_type_id++;
4938 }
4939
4940 return 0;
4941}
4942
4943static bool btf_resolve_valid(struct btf_verifier_env *env,
4944 const struct btf_type *t,
4945 u32 type_id)
4946{
4947 struct btf *btf = env->btf;
4948
4949 if (!env_type_is_resolved(env, type_id))
4950 return false;
4951
4952 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4953 return !btf_resolved_type_id(btf, type_id) &&
4954 !btf_resolved_type_size(btf, type_id);
4955
4956 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4957 return btf_resolved_type_id(btf, type_id) &&
4958 !btf_resolved_type_size(btf, type_id);
4959
4960 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4961 btf_type_is_var(t)) {
4962 t = btf_type_id_resolve(btf, &type_id);
4963 return t &&
4964 !btf_type_is_modifier(t) &&
4965 !btf_type_is_var(t) &&
4966 !btf_type_is_datasec(t);
4967 }
4968
4969 if (btf_type_is_array(t)) {
4970 const struct btf_array *array = btf_type_array(t);
4971 const struct btf_type *elem_type;
4972 u32 elem_type_id = array->type;
4973 u32 elem_size;
4974
4975 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4976 return elem_type && !btf_type_is_modifier(elem_type) &&
4977 (array->nelems * elem_size ==
4978 btf_resolved_type_size(btf, type_id));
4979 }
4980
4981 return false;
4982}
4983
4984static int btf_resolve(struct btf_verifier_env *env,
4985 const struct btf_type *t, u32 type_id)
4986{
4987 u32 save_log_type_id = env->log_type_id;
4988 const struct resolve_vertex *v;
4989 int err = 0;
4990
4991 env->resolve_mode = RESOLVE_TBD;
4992 env_stack_push(env, t, type_id);
4993 while (!err && (v = env_stack_peak(env))) {
4994 env->log_type_id = v->type_id;
4995 err = btf_type_ops(v->t)->resolve(env, v);
4996 }
4997
4998 env->log_type_id = type_id;
4999 if (err == -E2BIG) {
5000 btf_verifier_log_type(env, t,
5001 "Exceeded max resolving depth:%u",
5002 MAX_RESOLVE_DEPTH);
5003 } else if (err == -EEXIST) {
5004 btf_verifier_log_type(env, t, "Loop detected");
5005 }
5006
5007 /* Final sanity check */
5008 if (!err && !btf_resolve_valid(env, t, type_id)) {
5009 btf_verifier_log_type(env, t, "Invalid resolve state");
5010 err = -EINVAL;
5011 }
5012
5013 env->log_type_id = save_log_type_id;
5014 return err;
5015}
5016
5017static int btf_check_all_types(struct btf_verifier_env *env)
5018{
5019 struct btf *btf = env->btf;
5020 const struct btf_type *t;
5021 u32 type_id, i;
5022 int err;
5023
5024 err = env_resolve_init(env);
5025 if (err)
5026 return err;
5027
5028 env->phase++;
5029 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5030 type_id = btf->start_id + i;
5031 t = btf_type_by_id(btf, type_id);
5032
5033 env->log_type_id = type_id;
5034 if (btf_type_needs_resolve(t) &&
5035 !env_type_is_resolved(env, type_id)) {
5036 err = btf_resolve(env, t, type_id);
5037 if (err)
5038 return err;
5039 }
5040
5041 if (btf_type_is_func_proto(t)) {
5042 err = btf_func_proto_check(env, t);
5043 if (err)
5044 return err;
5045 }
5046 }
5047
5048 return 0;
5049}
5050
5051static int btf_parse_type_sec(struct btf_verifier_env *env)
5052{
5053 const struct btf_header *hdr = &env->btf->hdr;
5054 int err;
5055
5056 /* Type section must align to 4 bytes */
5057 if (hdr->type_off & (sizeof(u32) - 1)) {
5058 btf_verifier_log(env, "Unaligned type_off");
5059 return -EINVAL;
5060 }
5061
5062 if (!env->btf->base_btf && !hdr->type_len) {
5063 btf_verifier_log(env, "No type found");
5064 return -EINVAL;
5065 }
5066
5067 err = btf_check_all_metas(env);
5068 if (err)
5069 return err;
5070
5071 return btf_check_all_types(env);
5072}
5073
5074static int btf_parse_str_sec(struct btf_verifier_env *env)
5075{
5076 const struct btf_header *hdr;
5077 struct btf *btf = env->btf;
5078 const char *start, *end;
5079
5080 hdr = &btf->hdr;
5081 start = btf->nohdr_data + hdr->str_off;
5082 end = start + hdr->str_len;
5083
5084 if (end != btf->data + btf->data_size) {
5085 btf_verifier_log(env, "String section is not at the end");
5086 return -EINVAL;
5087 }
5088
5089 btf->strings = start;
5090
5091 if (btf->base_btf && !hdr->str_len)
5092 return 0;
5093 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5094 btf_verifier_log(env, "Invalid string section");
5095 return -EINVAL;
5096 }
5097 if (!btf->base_btf && start[0]) {
5098 btf_verifier_log(env, "Invalid string section");
5099 return -EINVAL;
5100 }
5101
5102 return 0;
5103}
5104
5105static const size_t btf_sec_info_offset[] = {
5106 offsetof(struct btf_header, type_off),
5107 offsetof(struct btf_header, str_off),
5108};
5109
5110static int btf_sec_info_cmp(const void *a, const void *b)
5111{
5112 const struct btf_sec_info *x = a;
5113 const struct btf_sec_info *y = b;
5114
5115 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5116}
5117
5118static int btf_check_sec_info(struct btf_verifier_env *env,
5119 u32 btf_data_size)
5120{
5121 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5122 u32 total, expected_total, i;
5123 const struct btf_header *hdr;
5124 const struct btf *btf;
5125
5126 btf = env->btf;
5127 hdr = &btf->hdr;
5128
5129 /* Populate the secs from hdr */
5130 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5131 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5132 btf_sec_info_offset[i]);
5133
5134 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5135 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5136
5137 /* Check for gaps and overlap among sections */
5138 total = 0;
5139 expected_total = btf_data_size - hdr->hdr_len;
5140 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5141 if (expected_total < secs[i].off) {
5142 btf_verifier_log(env, "Invalid section offset");
5143 return -EINVAL;
5144 }
5145 if (total < secs[i].off) {
5146 /* gap */
5147 btf_verifier_log(env, "Unsupported section found");
5148 return -EINVAL;
5149 }
5150 if (total > secs[i].off) {
5151 btf_verifier_log(env, "Section overlap found");
5152 return -EINVAL;
5153 }
5154 if (expected_total - total < secs[i].len) {
5155 btf_verifier_log(env,
5156 "Total section length too long");
5157 return -EINVAL;
5158 }
5159 total += secs[i].len;
5160 }
5161
5162 /* There is data other than hdr and known sections */
5163 if (expected_total != total) {
5164 btf_verifier_log(env, "Unsupported section found");
5165 return -EINVAL;
5166 }
5167
5168 return 0;
5169}
5170
5171static int btf_parse_hdr(struct btf_verifier_env *env)
5172{
5173 u32 hdr_len, hdr_copy, btf_data_size;
5174 const struct btf_header *hdr;
5175 struct btf *btf;
5176
5177 btf = env->btf;
5178 btf_data_size = btf->data_size;
5179
5180 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5181 btf_verifier_log(env, "hdr_len not found");
5182 return -EINVAL;
5183 }
5184
5185 hdr = btf->data;
5186 hdr_len = hdr->hdr_len;
5187 if (btf_data_size < hdr_len) {
5188 btf_verifier_log(env, "btf_header not found");
5189 return -EINVAL;
5190 }
5191
5192 /* Ensure the unsupported header fields are zero */
5193 if (hdr_len > sizeof(btf->hdr)) {
5194 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5195 u8 *end = btf->data + hdr_len;
5196
5197 for (; expected_zero < end; expected_zero++) {
5198 if (*expected_zero) {
5199 btf_verifier_log(env, "Unsupported btf_header");
5200 return -E2BIG;
5201 }
5202 }
5203 }
5204
5205 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5206 memcpy(&btf->hdr, btf->data, hdr_copy);
5207
5208 hdr = &btf->hdr;
5209
5210 btf_verifier_log_hdr(env, btf_data_size);
5211
5212 if (hdr->magic != BTF_MAGIC) {
5213 btf_verifier_log(env, "Invalid magic");
5214 return -EINVAL;
5215 }
5216
5217 if (hdr->version != BTF_VERSION) {
5218 btf_verifier_log(env, "Unsupported version");
5219 return -ENOTSUPP;
5220 }
5221
5222 if (hdr->flags) {
5223 btf_verifier_log(env, "Unsupported flags");
5224 return -ENOTSUPP;
5225 }
5226
5227 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5228 btf_verifier_log(env, "No data");
5229 return -EINVAL;
5230 }
5231
5232 return btf_check_sec_info(env, btf_data_size);
5233}
5234
5235static const char *alloc_obj_fields[] = {
5236 "bpf_spin_lock",
5237 "bpf_list_head",
5238 "bpf_list_node",
5239};
5240
5241static struct btf_struct_metas *
5242btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5243{
5244 union {
5245 struct btf_id_set set;
5246 struct {
5247 u32 _cnt;
5248 u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
5249 } _arr;
5250 } aof;
5251 struct btf_struct_metas *tab = NULL;
5252 int i, n, id, ret;
5253
5254 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5255 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5256
5257 memset(&aof, 0, sizeof(aof));
5258 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5259 /* Try to find whether this special type exists in user BTF, and
5260 * if so remember its ID so we can easily find it among members
5261 * of structs that we iterate in the next loop.
5262 */
5263 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5264 if (id < 0)
5265 continue;
5266 aof.set.ids[aof.set.cnt++] = id;
5267 }
5268
5269 if (!aof.set.cnt)
5270 return NULL;
5271 sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
5272
5273 n = btf_nr_types(btf);
5274 for (i = 1; i < n; i++) {
5275 struct btf_struct_metas *new_tab;
5276 const struct btf_member *member;
5277 struct btf_field_offs *foffs;
5278 struct btf_struct_meta *type;
5279 struct btf_record *record;
5280 const struct btf_type *t;
5281 int j, tab_cnt;
5282
5283 t = btf_type_by_id(btf, i);
5284 if (!t) {
5285 ret = -EINVAL;
5286 goto free;
5287 }
5288 if (!__btf_type_is_struct(t))
5289 continue;
5290
5291 cond_resched();
5292
5293 for_each_member(j, t, member) {
5294 if (btf_id_set_contains(&aof.set, member->type))
5295 goto parse;
5296 }
5297 continue;
5298 parse:
5299 tab_cnt = tab ? tab->cnt : 0;
5300 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5301 GFP_KERNEL | __GFP_NOWARN);
5302 if (!new_tab) {
5303 ret = -ENOMEM;
5304 goto free;
5305 }
5306 if (!tab)
5307 new_tab->cnt = 0;
5308 tab = new_tab;
5309
5310 type = &tab->types[tab->cnt];
5311 type->btf_id = i;
5312 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE, t->size);
5313 /* The record cannot be unset, treat it as an error if so */
5314 if (IS_ERR_OR_NULL(record)) {
5315 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5316 goto free;
5317 }
5318 foffs = btf_parse_field_offs(record);
5319 /* We need the field_offs to be valid for a valid record,
5320 * either both should be set or both should be unset.
5321 */
5322 if (IS_ERR_OR_NULL(foffs)) {
5323 btf_record_free(record);
5324 ret = -EFAULT;
5325 goto free;
5326 }
5327 type->record = record;
5328 type->field_offs = foffs;
5329 tab->cnt++;
5330 }
5331 return tab;
5332free:
5333 btf_struct_metas_free(tab);
5334 return ERR_PTR(ret);
5335}
5336
5337struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5338{
5339 struct btf_struct_metas *tab;
5340
5341 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5342 tab = btf->struct_meta_tab;
5343 if (!tab)
5344 return NULL;
5345 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5346}
5347
5348static int btf_check_type_tags(struct btf_verifier_env *env,
5349 struct btf *btf, int start_id)
5350{
5351 int i, n, good_id = start_id - 1;
5352 bool in_tags;
5353
5354 n = btf_nr_types(btf);
5355 for (i = start_id; i < n; i++) {
5356 const struct btf_type *t;
5357 int chain_limit = 32;
5358 u32 cur_id = i;
5359
5360 t = btf_type_by_id(btf, i);
5361 if (!t)
5362 return -EINVAL;
5363 if (!btf_type_is_modifier(t))
5364 continue;
5365
5366 cond_resched();
5367
5368 in_tags = btf_type_is_type_tag(t);
5369 while (btf_type_is_modifier(t)) {
5370 if (!chain_limit--) {
5371 btf_verifier_log(env, "Max chain length or cycle detected");
5372 return -ELOOP;
5373 }
5374 if (btf_type_is_type_tag(t)) {
5375 if (!in_tags) {
5376 btf_verifier_log(env, "Type tags don't precede modifiers");
5377 return -EINVAL;
5378 }
5379 } else if (in_tags) {
5380 in_tags = false;
5381 }
5382 if (cur_id <= good_id)
5383 break;
5384 /* Move to next type */
5385 cur_id = t->type;
5386 t = btf_type_by_id(btf, cur_id);
5387 if (!t)
5388 return -EINVAL;
5389 }
5390 good_id = i;
5391 }
5392 return 0;
5393}
5394
5395static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
5396 u32 log_level, char __user *log_ubuf, u32 log_size)
5397{
5398 struct btf_struct_metas *struct_meta_tab;
5399 struct btf_verifier_env *env = NULL;
5400 struct bpf_verifier_log *log;
5401 struct btf *btf = NULL;
5402 u8 *data;
5403 int err;
5404
5405 if (btf_data_size > BTF_MAX_SIZE)
5406 return ERR_PTR(-E2BIG);
5407
5408 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5409 if (!env)
5410 return ERR_PTR(-ENOMEM);
5411
5412 log = &env->log;
5413 if (log_level || log_ubuf || log_size) {
5414 /* user requested verbose verifier output
5415 * and supplied buffer to store the verification trace
5416 */
5417 log->level = log_level;
5418 log->ubuf = log_ubuf;
5419 log->len_total = log_size;
5420
5421 /* log attributes have to be sane */
5422 if (!bpf_verifier_log_attr_valid(log)) {
5423 err = -EINVAL;
5424 goto errout;
5425 }
5426 }
5427
5428 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5429 if (!btf) {
5430 err = -ENOMEM;
5431 goto errout;
5432 }
5433 env->btf = btf;
5434
5435 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
5436 if (!data) {
5437 err = -ENOMEM;
5438 goto errout;
5439 }
5440
5441 btf->data = data;
5442 btf->data_size = btf_data_size;
5443
5444 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
5445 err = -EFAULT;
5446 goto errout;
5447 }
5448
5449 err = btf_parse_hdr(env);
5450 if (err)
5451 goto errout;
5452
5453 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5454
5455 err = btf_parse_str_sec(env);
5456 if (err)
5457 goto errout;
5458
5459 err = btf_parse_type_sec(env);
5460 if (err)
5461 goto errout;
5462
5463 err = btf_check_type_tags(env, btf, 1);
5464 if (err)
5465 goto errout;
5466
5467 struct_meta_tab = btf_parse_struct_metas(log, btf);
5468 if (IS_ERR(struct_meta_tab)) {
5469 err = PTR_ERR(struct_meta_tab);
5470 goto errout;
5471 }
5472 btf->struct_meta_tab = struct_meta_tab;
5473
5474 if (struct_meta_tab) {
5475 int i;
5476
5477 for (i = 0; i < struct_meta_tab->cnt; i++) {
5478 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5479 if (err < 0)
5480 goto errout_meta;
5481 }
5482 }
5483
5484 if (log->level && bpf_verifier_log_full(log)) {
5485 err = -ENOSPC;
5486 goto errout_meta;
5487 }
5488
5489 btf_verifier_env_free(env);
5490 refcount_set(&btf->refcnt, 1);
5491 return btf;
5492
5493errout_meta:
5494 btf_free_struct_meta_tab(btf);
5495errout:
5496 btf_verifier_env_free(env);
5497 if (btf)
5498 btf_free(btf);
5499 return ERR_PTR(err);
5500}
5501
5502extern char __weak __start_BTF[];
5503extern char __weak __stop_BTF[];
5504extern struct btf *btf_vmlinux;
5505
5506#define BPF_MAP_TYPE(_id, _ops)
5507#define BPF_LINK_TYPE(_id, _name)
5508static union {
5509 struct bpf_ctx_convert {
5510#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5511 prog_ctx_type _id##_prog; \
5512 kern_ctx_type _id##_kern;
5513#include <linux/bpf_types.h>
5514#undef BPF_PROG_TYPE
5515 } *__t;
5516 /* 't' is written once under lock. Read many times. */
5517 const struct btf_type *t;
5518} bpf_ctx_convert;
5519enum {
5520#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5521 __ctx_convert##_id,
5522#include <linux/bpf_types.h>
5523#undef BPF_PROG_TYPE
5524 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5525};
5526static u8 bpf_ctx_convert_map[] = {
5527#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5528 [_id] = __ctx_convert##_id,
5529#include <linux/bpf_types.h>
5530#undef BPF_PROG_TYPE
5531 0, /* avoid empty array */
5532};
5533#undef BPF_MAP_TYPE
5534#undef BPF_LINK_TYPE
5535
5536const struct btf_member *
5537btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5538 const struct btf_type *t, enum bpf_prog_type prog_type,
5539 int arg)
5540{
5541 const struct btf_type *conv_struct;
5542 const struct btf_type *ctx_struct;
5543 const struct btf_member *ctx_type;
5544 const char *tname, *ctx_tname;
5545
5546 conv_struct = bpf_ctx_convert.t;
5547 if (!conv_struct) {
5548 bpf_log(log, "btf_vmlinux is malformed\n");
5549 return NULL;
5550 }
5551 t = btf_type_by_id(btf, t->type);
5552 while (btf_type_is_modifier(t))
5553 t = btf_type_by_id(btf, t->type);
5554 if (!btf_type_is_struct(t)) {
5555 /* Only pointer to struct is supported for now.
5556 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5557 * is not supported yet.
5558 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5559 */
5560 return NULL;
5561 }
5562 tname = btf_name_by_offset(btf, t->name_off);
5563 if (!tname) {
5564 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5565 return NULL;
5566 }
5567 /* prog_type is valid bpf program type. No need for bounds check. */
5568 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5569 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
5570 * Like 'struct __sk_buff'
5571 */
5572 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
5573 if (!ctx_struct)
5574 /* should not happen */
5575 return NULL;
5576 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
5577 if (!ctx_tname) {
5578 /* should not happen */
5579 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5580 return NULL;
5581 }
5582 /* only compare that prog's ctx type name is the same as
5583 * kernel expects. No need to compare field by field.
5584 * It's ok for bpf prog to do:
5585 * struct __sk_buff {};
5586 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5587 * { // no fields of skb are ever used }
5588 */
5589 if (strcmp(ctx_tname, tname))
5590 return NULL;
5591 return ctx_type;
5592}
5593
5594static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5595 struct btf *btf,
5596 const struct btf_type *t,
5597 enum bpf_prog_type prog_type,
5598 int arg)
5599{
5600 const struct btf_member *prog_ctx_type, *kern_ctx_type;
5601
5602 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
5603 if (!prog_ctx_type)
5604 return -ENOENT;
5605 kern_ctx_type = prog_ctx_type + 1;
5606 return kern_ctx_type->type;
5607}
5608
5609int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
5610{
5611 const struct btf_member *kctx_member;
5612 const struct btf_type *conv_struct;
5613 const struct btf_type *kctx_type;
5614 u32 kctx_type_id;
5615
5616 conv_struct = bpf_ctx_convert.t;
5617 /* get member for kernel ctx type */
5618 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5619 kctx_type_id = kctx_member->type;
5620 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
5621 if (!btf_type_is_struct(kctx_type)) {
5622 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
5623 return -EINVAL;
5624 }
5625
5626 return kctx_type_id;
5627}
5628
5629BTF_ID_LIST(bpf_ctx_convert_btf_id)
5630BTF_ID(struct, bpf_ctx_convert)
5631
5632struct btf *btf_parse_vmlinux(void)
5633{
5634 struct btf_verifier_env *env = NULL;
5635 struct bpf_verifier_log *log;
5636 struct btf *btf = NULL;
5637 int err;
5638
5639 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5640 if (!env)
5641 return ERR_PTR(-ENOMEM);
5642
5643 log = &env->log;
5644 log->level = BPF_LOG_KERNEL;
5645
5646 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5647 if (!btf) {
5648 err = -ENOMEM;
5649 goto errout;
5650 }
5651 env->btf = btf;
5652
5653 btf->data = __start_BTF;
5654 btf->data_size = __stop_BTF - __start_BTF;
5655 btf->kernel_btf = true;
5656 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5657
5658 err = btf_parse_hdr(env);
5659 if (err)
5660 goto errout;
5661
5662 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5663
5664 err = btf_parse_str_sec(env);
5665 if (err)
5666 goto errout;
5667
5668 err = btf_check_all_metas(env);
5669 if (err)
5670 goto errout;
5671
5672 err = btf_check_type_tags(env, btf, 1);
5673 if (err)
5674 goto errout;
5675
5676 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
5677 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5678
5679 bpf_struct_ops_init(btf, log);
5680
5681 refcount_set(&btf->refcnt, 1);
5682
5683 err = btf_alloc_id(btf);
5684 if (err)
5685 goto errout;
5686
5687 btf_verifier_env_free(env);
5688 return btf;
5689
5690errout:
5691 btf_verifier_env_free(env);
5692 if (btf) {
5693 kvfree(btf->types);
5694 kfree(btf);
5695 }
5696 return ERR_PTR(err);
5697}
5698
5699#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5700
5701static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5702{
5703 struct btf_verifier_env *env = NULL;
5704 struct bpf_verifier_log *log;
5705 struct btf *btf = NULL, *base_btf;
5706 int err;
5707
5708 base_btf = bpf_get_btf_vmlinux();
5709 if (IS_ERR(base_btf))
5710 return base_btf;
5711 if (!base_btf)
5712 return ERR_PTR(-EINVAL);
5713
5714 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5715 if (!env)
5716 return ERR_PTR(-ENOMEM);
5717
5718 log = &env->log;
5719 log->level = BPF_LOG_KERNEL;
5720
5721 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5722 if (!btf) {
5723 err = -ENOMEM;
5724 goto errout;
5725 }
5726 env->btf = btf;
5727
5728 btf->base_btf = base_btf;
5729 btf->start_id = base_btf->nr_types;
5730 btf->start_str_off = base_btf->hdr.str_len;
5731 btf->kernel_btf = true;
5732 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5733
5734 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5735 if (!btf->data) {
5736 err = -ENOMEM;
5737 goto errout;
5738 }
5739 memcpy(btf->data, data, data_size);
5740 btf->data_size = data_size;
5741
5742 err = btf_parse_hdr(env);
5743 if (err)
5744 goto errout;
5745
5746 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5747
5748 err = btf_parse_str_sec(env);
5749 if (err)
5750 goto errout;
5751
5752 err = btf_check_all_metas(env);
5753 if (err)
5754 goto errout;
5755
5756 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
5757 if (err)
5758 goto errout;
5759
5760 btf_verifier_env_free(env);
5761 refcount_set(&btf->refcnt, 1);
5762 return btf;
5763
5764errout:
5765 btf_verifier_env_free(env);
5766 if (btf) {
5767 kvfree(btf->data);
5768 kvfree(btf->types);
5769 kfree(btf);
5770 }
5771 return ERR_PTR(err);
5772}
5773
5774#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
5775
5776struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
5777{
5778 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5779
5780 if (tgt_prog)
5781 return tgt_prog->aux->btf;
5782 else
5783 return prog->aux->attach_btf;
5784}
5785
5786static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
5787{
5788 /* t comes in already as a pointer */
5789 t = btf_type_by_id(btf, t->type);
5790
5791 /* allow const */
5792 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
5793 t = btf_type_by_id(btf, t->type);
5794
5795 return btf_type_is_int(t);
5796}
5797
5798static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
5799 int off)
5800{
5801 const struct btf_param *args;
5802 const struct btf_type *t;
5803 u32 offset = 0, nr_args;
5804 int i;
5805
5806 if (!func_proto)
5807 return off / 8;
5808
5809 nr_args = btf_type_vlen(func_proto);
5810 args = (const struct btf_param *)(func_proto + 1);
5811 for (i = 0; i < nr_args; i++) {
5812 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5813 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5814 if (off < offset)
5815 return i;
5816 }
5817
5818 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
5819 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5820 if (off < offset)
5821 return nr_args;
5822
5823 return nr_args + 1;
5824}
5825
5826static bool prog_args_trusted(const struct bpf_prog *prog)
5827{
5828 enum bpf_attach_type atype = prog->expected_attach_type;
5829
5830 switch (prog->type) {
5831 case BPF_PROG_TYPE_TRACING:
5832 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
5833 case BPF_PROG_TYPE_LSM:
5834 return bpf_lsm_is_trusted(prog);
5835 case BPF_PROG_TYPE_STRUCT_OPS:
5836 return true;
5837 default:
5838 return false;
5839 }
5840}
5841
5842bool btf_ctx_access(int off, int size, enum bpf_access_type type,
5843 const struct bpf_prog *prog,
5844 struct bpf_insn_access_aux *info)
5845{
5846 const struct btf_type *t = prog->aux->attach_func_proto;
5847 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5848 struct btf *btf = bpf_prog_get_target_btf(prog);
5849 const char *tname = prog->aux->attach_func_name;
5850 struct bpf_verifier_log *log = info->log;
5851 const struct btf_param *args;
5852 const char *tag_value;
5853 u32 nr_args, arg;
5854 int i, ret;
5855
5856 if (off % 8) {
5857 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
5858 tname, off);
5859 return false;
5860 }
5861 arg = get_ctx_arg_idx(btf, t, off);
5862 args = (const struct btf_param *)(t + 1);
5863 /* if (t == NULL) Fall back to default BPF prog with
5864 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
5865 */
5866 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
5867 if (prog->aux->attach_btf_trace) {
5868 /* skip first 'void *__data' argument in btf_trace_##name typedef */
5869 args++;
5870 nr_args--;
5871 }
5872
5873 if (arg > nr_args) {
5874 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5875 tname, arg + 1);
5876 return false;
5877 }
5878
5879 if (arg == nr_args) {
5880 switch (prog->expected_attach_type) {
5881 case BPF_LSM_CGROUP:
5882 case BPF_LSM_MAC:
5883 case BPF_TRACE_FEXIT:
5884 /* When LSM programs are attached to void LSM hooks
5885 * they use FEXIT trampolines and when attached to
5886 * int LSM hooks, they use MODIFY_RETURN trampolines.
5887 *
5888 * While the LSM programs are BPF_MODIFY_RETURN-like
5889 * the check:
5890 *
5891 * if (ret_type != 'int')
5892 * return -EINVAL;
5893 *
5894 * is _not_ done here. This is still safe as LSM hooks
5895 * have only void and int return types.
5896 */
5897 if (!t)
5898 return true;
5899 t = btf_type_by_id(btf, t->type);
5900 break;
5901 case BPF_MODIFY_RETURN:
5902 /* For now the BPF_MODIFY_RETURN can only be attached to
5903 * functions that return an int.
5904 */
5905 if (!t)
5906 return false;
5907
5908 t = btf_type_skip_modifiers(btf, t->type, NULL);
5909 if (!btf_type_is_small_int(t)) {
5910 bpf_log(log,
5911 "ret type %s not allowed for fmod_ret\n",
5912 btf_type_str(t));
5913 return false;
5914 }
5915 break;
5916 default:
5917 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5918 tname, arg + 1);
5919 return false;
5920 }
5921 } else {
5922 if (!t)
5923 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
5924 return true;
5925 t = btf_type_by_id(btf, args[arg].type);
5926 }
5927
5928 /* skip modifiers */
5929 while (btf_type_is_modifier(t))
5930 t = btf_type_by_id(btf, t->type);
5931 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
5932 /* accessing a scalar */
5933 return true;
5934 if (!btf_type_is_ptr(t)) {
5935 bpf_log(log,
5936 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
5937 tname, arg,
5938 __btf_name_by_offset(btf, t->name_off),
5939 btf_type_str(t));
5940 return false;
5941 }
5942
5943 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
5944 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5945 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5946 u32 type, flag;
5947
5948 type = base_type(ctx_arg_info->reg_type);
5949 flag = type_flag(ctx_arg_info->reg_type);
5950 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
5951 (flag & PTR_MAYBE_NULL)) {
5952 info->reg_type = ctx_arg_info->reg_type;
5953 return true;
5954 }
5955 }
5956
5957 if (t->type == 0)
5958 /* This is a pointer to void.
5959 * It is the same as scalar from the verifier safety pov.
5960 * No further pointer walking is allowed.
5961 */
5962 return true;
5963
5964 if (is_int_ptr(btf, t))
5965 return true;
5966
5967 /* this is a pointer to another type */
5968 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5969 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5970
5971 if (ctx_arg_info->offset == off) {
5972 if (!ctx_arg_info->btf_id) {
5973 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
5974 return false;
5975 }
5976
5977 info->reg_type = ctx_arg_info->reg_type;
5978 info->btf = btf_vmlinux;
5979 info->btf_id = ctx_arg_info->btf_id;
5980 return true;
5981 }
5982 }
5983
5984 info->reg_type = PTR_TO_BTF_ID;
5985 if (prog_args_trusted(prog))
5986 info->reg_type |= PTR_TRUSTED;
5987
5988 if (tgt_prog) {
5989 enum bpf_prog_type tgt_type;
5990
5991 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
5992 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5993 else
5994 tgt_type = tgt_prog->type;
5995
5996 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5997 if (ret > 0) {
5998 info->btf = btf_vmlinux;
5999 info->btf_id = ret;
6000 return true;
6001 } else {
6002 return false;
6003 }
6004 }
6005
6006 info->btf = btf;
6007 info->btf_id = t->type;
6008 t = btf_type_by_id(btf, t->type);
6009
6010 if (btf_type_is_type_tag(t)) {
6011 tag_value = __btf_name_by_offset(btf, t->name_off);
6012 if (strcmp(tag_value, "user") == 0)
6013 info->reg_type |= MEM_USER;
6014 if (strcmp(tag_value, "percpu") == 0)
6015 info->reg_type |= MEM_PERCPU;
6016 }
6017
6018 /* skip modifiers */
6019 while (btf_type_is_modifier(t)) {
6020 info->btf_id = t->type;
6021 t = btf_type_by_id(btf, t->type);
6022 }
6023 if (!btf_type_is_struct(t)) {
6024 bpf_log(log,
6025 "func '%s' arg%d type %s is not a struct\n",
6026 tname, arg, btf_type_str(t));
6027 return false;
6028 }
6029 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6030 tname, arg, info->btf_id, btf_type_str(t),
6031 __btf_name_by_offset(btf, t->name_off));
6032 return true;
6033}
6034
6035enum bpf_struct_walk_result {
6036 /* < 0 error */
6037 WALK_SCALAR = 0,
6038 WALK_PTR,
6039 WALK_STRUCT,
6040};
6041
6042static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6043 const struct btf_type *t, int off, int size,
6044 u32 *next_btf_id, enum bpf_type_flag *flag)
6045{
6046 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6047 const struct btf_type *mtype, *elem_type = NULL;
6048 const struct btf_member *member;
6049 const char *tname, *mname, *tag_value;
6050 u32 vlen, elem_id, mid;
6051
6052again:
6053 tname = __btf_name_by_offset(btf, t->name_off);
6054 if (!btf_type_is_struct(t)) {
6055 bpf_log(log, "Type '%s' is not a struct\n", tname);
6056 return -EINVAL;
6057 }
6058
6059 vlen = btf_type_vlen(t);
6060 if (off + size > t->size) {
6061 /* If the last element is a variable size array, we may
6062 * need to relax the rule.
6063 */
6064 struct btf_array *array_elem;
6065
6066 if (vlen == 0)
6067 goto error;
6068
6069 member = btf_type_member(t) + vlen - 1;
6070 mtype = btf_type_skip_modifiers(btf, member->type,
6071 NULL);
6072 if (!btf_type_is_array(mtype))
6073 goto error;
6074
6075 array_elem = (struct btf_array *)(mtype + 1);
6076 if (array_elem->nelems != 0)
6077 goto error;
6078
6079 moff = __btf_member_bit_offset(t, member) / 8;
6080 if (off < moff)
6081 goto error;
6082
6083 /* Only allow structure for now, can be relaxed for
6084 * other types later.
6085 */
6086 t = btf_type_skip_modifiers(btf, array_elem->type,
6087 NULL);
6088 if (!btf_type_is_struct(t))
6089 goto error;
6090
6091 off = (off - moff) % t->size;
6092 goto again;
6093
6094error:
6095 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6096 tname, off, size);
6097 return -EACCES;
6098 }
6099
6100 for_each_member(i, t, member) {
6101 /* offset of the field in bytes */
6102 moff = __btf_member_bit_offset(t, member) / 8;
6103 if (off + size <= moff)
6104 /* won't find anything, field is already too far */
6105 break;
6106
6107 if (__btf_member_bitfield_size(t, member)) {
6108 u32 end_bit = __btf_member_bit_offset(t, member) +
6109 __btf_member_bitfield_size(t, member);
6110
6111 /* off <= moff instead of off == moff because clang
6112 * does not generate a BTF member for anonymous
6113 * bitfield like the ":16" here:
6114 * struct {
6115 * int :16;
6116 * int x:8;
6117 * };
6118 */
6119 if (off <= moff &&
6120 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6121 return WALK_SCALAR;
6122
6123 /* off may be accessing a following member
6124 *
6125 * or
6126 *
6127 * Doing partial access at either end of this
6128 * bitfield. Continue on this case also to
6129 * treat it as not accessing this bitfield
6130 * and eventually error out as field not
6131 * found to keep it simple.
6132 * It could be relaxed if there was a legit
6133 * partial access case later.
6134 */
6135 continue;
6136 }
6137
6138 /* In case of "off" is pointing to holes of a struct */
6139 if (off < moff)
6140 break;
6141
6142 /* type of the field */
6143 mid = member->type;
6144 mtype = btf_type_by_id(btf, member->type);
6145 mname = __btf_name_by_offset(btf, member->name_off);
6146
6147 mtype = __btf_resolve_size(btf, mtype, &msize,
6148 &elem_type, &elem_id, &total_nelems,
6149 &mid);
6150 if (IS_ERR(mtype)) {
6151 bpf_log(log, "field %s doesn't have size\n", mname);
6152 return -EFAULT;
6153 }
6154
6155 mtrue_end = moff + msize;
6156 if (off >= mtrue_end)
6157 /* no overlap with member, keep iterating */
6158 continue;
6159
6160 if (btf_type_is_array(mtype)) {
6161 u32 elem_idx;
6162
6163 /* __btf_resolve_size() above helps to
6164 * linearize a multi-dimensional array.
6165 *
6166 * The logic here is treating an array
6167 * in a struct as the following way:
6168 *
6169 * struct outer {
6170 * struct inner array[2][2];
6171 * };
6172 *
6173 * looks like:
6174 *
6175 * struct outer {
6176 * struct inner array_elem0;
6177 * struct inner array_elem1;
6178 * struct inner array_elem2;
6179 * struct inner array_elem3;
6180 * };
6181 *
6182 * When accessing outer->array[1][0], it moves
6183 * moff to "array_elem2", set mtype to
6184 * "struct inner", and msize also becomes
6185 * sizeof(struct inner). Then most of the
6186 * remaining logic will fall through without
6187 * caring the current member is an array or
6188 * not.
6189 *
6190 * Unlike mtype/msize/moff, mtrue_end does not
6191 * change. The naming difference ("_true") tells
6192 * that it is not always corresponding to
6193 * the current mtype/msize/moff.
6194 * It is the true end of the current
6195 * member (i.e. array in this case). That
6196 * will allow an int array to be accessed like
6197 * a scratch space,
6198 * i.e. allow access beyond the size of
6199 * the array's element as long as it is
6200 * within the mtrue_end boundary.
6201 */
6202
6203 /* skip empty array */
6204 if (moff == mtrue_end)
6205 continue;
6206
6207 msize /= total_nelems;
6208 elem_idx = (off - moff) / msize;
6209 moff += elem_idx * msize;
6210 mtype = elem_type;
6211 mid = elem_id;
6212 }
6213
6214 /* the 'off' we're looking for is either equal to start
6215 * of this field or inside of this struct
6216 */
6217 if (btf_type_is_struct(mtype)) {
6218 /* our field must be inside that union or struct */
6219 t = mtype;
6220
6221 /* return if the offset matches the member offset */
6222 if (off == moff) {
6223 *next_btf_id = mid;
6224 return WALK_STRUCT;
6225 }
6226
6227 /* adjust offset we're looking for */
6228 off -= moff;
6229 goto again;
6230 }
6231
6232 if (btf_type_is_ptr(mtype)) {
6233 const struct btf_type *stype, *t;
6234 enum bpf_type_flag tmp_flag = 0;
6235 u32 id;
6236
6237 if (msize != size || off != moff) {
6238 bpf_log(log,
6239 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6240 mname, moff, tname, off, size);
6241 return -EACCES;
6242 }
6243
6244 /* check type tag */
6245 t = btf_type_by_id(btf, mtype->type);
6246 if (btf_type_is_type_tag(t)) {
6247 tag_value = __btf_name_by_offset(btf, t->name_off);
6248 /* check __user tag */
6249 if (strcmp(tag_value, "user") == 0)
6250 tmp_flag = MEM_USER;
6251 /* check __percpu tag */
6252 if (strcmp(tag_value, "percpu") == 0)
6253 tmp_flag = MEM_PERCPU;
6254 /* check __rcu tag */
6255 if (strcmp(tag_value, "rcu") == 0)
6256 tmp_flag = MEM_RCU;
6257 }
6258
6259 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6260 if (btf_type_is_struct(stype)) {
6261 *next_btf_id = id;
6262 *flag = tmp_flag;
6263 return WALK_PTR;
6264 }
6265 }
6266
6267 /* Allow more flexible access within an int as long as
6268 * it is within mtrue_end.
6269 * Since mtrue_end could be the end of an array,
6270 * that also allows using an array of int as a scratch
6271 * space. e.g. skb->cb[].
6272 */
6273 if (off + size > mtrue_end) {
6274 bpf_log(log,
6275 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6276 mname, mtrue_end, tname, off, size);
6277 return -EACCES;
6278 }
6279
6280 return WALK_SCALAR;
6281 }
6282 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6283 return -EINVAL;
6284}
6285
6286int btf_struct_access(struct bpf_verifier_log *log,
6287 const struct bpf_reg_state *reg,
6288 int off, int size, enum bpf_access_type atype __maybe_unused,
6289 u32 *next_btf_id, enum bpf_type_flag *flag)
6290{
6291 const struct btf *btf = reg->btf;
6292 enum bpf_type_flag tmp_flag = 0;
6293 const struct btf_type *t;
6294 u32 id = reg->btf_id;
6295 int err;
6296
6297 while (type_is_alloc(reg->type)) {
6298 struct btf_struct_meta *meta;
6299 struct btf_record *rec;
6300 int i;
6301
6302 meta = btf_find_struct_meta(btf, id);
6303 if (!meta)
6304 break;
6305 rec = meta->record;
6306 for (i = 0; i < rec->cnt; i++) {
6307 struct btf_field *field = &rec->fields[i];
6308 u32 offset = field->offset;
6309 if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
6310 bpf_log(log,
6311 "direct access to %s is disallowed\n",
6312 btf_field_type_name(field->type));
6313 return -EACCES;
6314 }
6315 }
6316 break;
6317 }
6318
6319 t = btf_type_by_id(btf, id);
6320 do {
6321 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
6322
6323 switch (err) {
6324 case WALK_PTR:
6325 /* For local types, the destination register cannot
6326 * become a pointer again.
6327 */
6328 if (type_is_alloc(reg->type))
6329 return SCALAR_VALUE;
6330 /* If we found the pointer or scalar on t+off,
6331 * we're done.
6332 */
6333 *next_btf_id = id;
6334 *flag = tmp_flag;
6335 return PTR_TO_BTF_ID;
6336 case WALK_SCALAR:
6337 return SCALAR_VALUE;
6338 case WALK_STRUCT:
6339 /* We found nested struct, so continue the search
6340 * by diving in it. At this point the offset is
6341 * aligned with the new type, so set it to 0.
6342 */
6343 t = btf_type_by_id(btf, id);
6344 off = 0;
6345 break;
6346 default:
6347 /* It's either error or unknown return value..
6348 * scream and leave.
6349 */
6350 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6351 return -EINVAL;
6352 return err;
6353 }
6354 } while (t);
6355
6356 return -EINVAL;
6357}
6358
6359/* Check that two BTF types, each specified as an BTF object + id, are exactly
6360 * the same. Trivial ID check is not enough due to module BTFs, because we can
6361 * end up with two different module BTFs, but IDs point to the common type in
6362 * vmlinux BTF.
6363 */
6364bool btf_types_are_same(const struct btf *btf1, u32 id1,
6365 const struct btf *btf2, u32 id2)
6366{
6367 if (id1 != id2)
6368 return false;
6369 if (btf1 == btf2)
6370 return true;
6371 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6372}
6373
6374bool btf_struct_ids_match(struct bpf_verifier_log *log,
6375 const struct btf *btf, u32 id, int off,
6376 const struct btf *need_btf, u32 need_type_id,
6377 bool strict)
6378{
6379 const struct btf_type *type;
6380 enum bpf_type_flag flag;
6381 int err;
6382
6383 /* Are we already done? */
6384 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6385 return true;
6386 /* In case of strict type match, we do not walk struct, the top level
6387 * type match must succeed. When strict is true, off should have already
6388 * been 0.
6389 */
6390 if (strict)
6391 return false;
6392again:
6393 type = btf_type_by_id(btf, id);
6394 if (!type)
6395 return false;
6396 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
6397 if (err != WALK_STRUCT)
6398 return false;
6399
6400 /* We found nested struct object. If it matches
6401 * the requested ID, we're done. Otherwise let's
6402 * continue the search with offset 0 in the new
6403 * type.
6404 */
6405 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6406 off = 0;
6407 goto again;
6408 }
6409
6410 return true;
6411}
6412
6413static int __get_type_size(struct btf *btf, u32 btf_id,
6414 const struct btf_type **ret_type)
6415{
6416 const struct btf_type *t;
6417
6418 *ret_type = btf_type_by_id(btf, 0);
6419 if (!btf_id)
6420 /* void */
6421 return 0;
6422 t = btf_type_by_id(btf, btf_id);
6423 while (t && btf_type_is_modifier(t))
6424 t = btf_type_by_id(btf, t->type);
6425 if (!t)
6426 return -EINVAL;
6427 *ret_type = t;
6428 if (btf_type_is_ptr(t))
6429 /* kernel size of pointer. Not BPF's size of pointer*/
6430 return sizeof(void *);
6431 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6432 return t->size;
6433 return -EINVAL;
6434}
6435
6436int btf_distill_func_proto(struct bpf_verifier_log *log,
6437 struct btf *btf,
6438 const struct btf_type *func,
6439 const char *tname,
6440 struct btf_func_model *m)
6441{
6442 const struct btf_param *args;
6443 const struct btf_type *t;
6444 u32 i, nargs;
6445 int ret;
6446
6447 if (!func) {
6448 /* BTF function prototype doesn't match the verifier types.
6449 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
6450 */
6451 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
6452 m->arg_size[i] = 8;
6453 m->arg_flags[i] = 0;
6454 }
6455 m->ret_size = 8;
6456 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
6457 return 0;
6458 }
6459 args = (const struct btf_param *)(func + 1);
6460 nargs = btf_type_vlen(func);
6461 if (nargs > MAX_BPF_FUNC_ARGS) {
6462 bpf_log(log,
6463 "The function %s has %d arguments. Too many.\n",
6464 tname, nargs);
6465 return -EINVAL;
6466 }
6467 ret = __get_type_size(btf, func->type, &t);
6468 if (ret < 0 || __btf_type_is_struct(t)) {
6469 bpf_log(log,
6470 "The function %s return type %s is unsupported.\n",
6471 tname, btf_type_str(t));
6472 return -EINVAL;
6473 }
6474 m->ret_size = ret;
6475
6476 for (i = 0; i < nargs; i++) {
6477 if (i == nargs - 1 && args[i].type == 0) {
6478 bpf_log(log,
6479 "The function %s with variable args is unsupported.\n",
6480 tname);
6481 return -EINVAL;
6482 }
6483 ret = __get_type_size(btf, args[i].type, &t);
6484
6485 /* No support of struct argument size greater than 16 bytes */
6486 if (ret < 0 || ret > 16) {
6487 bpf_log(log,
6488 "The function %s arg%d type %s is unsupported.\n",
6489 tname, i, btf_type_str(t));
6490 return -EINVAL;
6491 }
6492 if (ret == 0) {
6493 bpf_log(log,
6494 "The function %s has malformed void argument.\n",
6495 tname);
6496 return -EINVAL;
6497 }
6498 m->arg_size[i] = ret;
6499 m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0;
6500 }
6501 m->nr_args = nargs;
6502 return 0;
6503}
6504
6505/* Compare BTFs of two functions assuming only scalars and pointers to context.
6506 * t1 points to BTF_KIND_FUNC in btf1
6507 * t2 points to BTF_KIND_FUNC in btf2
6508 * Returns:
6509 * EINVAL - function prototype mismatch
6510 * EFAULT - verifier bug
6511 * 0 - 99% match. The last 1% is validated by the verifier.
6512 */
6513static int btf_check_func_type_match(struct bpf_verifier_log *log,
6514 struct btf *btf1, const struct btf_type *t1,
6515 struct btf *btf2, const struct btf_type *t2)
6516{
6517 const struct btf_param *args1, *args2;
6518 const char *fn1, *fn2, *s1, *s2;
6519 u32 nargs1, nargs2, i;
6520
6521 fn1 = btf_name_by_offset(btf1, t1->name_off);
6522 fn2 = btf_name_by_offset(btf2, t2->name_off);
6523
6524 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6525 bpf_log(log, "%s() is not a global function\n", fn1);
6526 return -EINVAL;
6527 }
6528 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6529 bpf_log(log, "%s() is not a global function\n", fn2);
6530 return -EINVAL;
6531 }
6532
6533 t1 = btf_type_by_id(btf1, t1->type);
6534 if (!t1 || !btf_type_is_func_proto(t1))
6535 return -EFAULT;
6536 t2 = btf_type_by_id(btf2, t2->type);
6537 if (!t2 || !btf_type_is_func_proto(t2))
6538 return -EFAULT;
6539
6540 args1 = (const struct btf_param *)(t1 + 1);
6541 nargs1 = btf_type_vlen(t1);
6542 args2 = (const struct btf_param *)(t2 + 1);
6543 nargs2 = btf_type_vlen(t2);
6544
6545 if (nargs1 != nargs2) {
6546 bpf_log(log, "%s() has %d args while %s() has %d args\n",
6547 fn1, nargs1, fn2, nargs2);
6548 return -EINVAL;
6549 }
6550
6551 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6552 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6553 if (t1->info != t2->info) {
6554 bpf_log(log,
6555 "Return type %s of %s() doesn't match type %s of %s()\n",
6556 btf_type_str(t1), fn1,
6557 btf_type_str(t2), fn2);
6558 return -EINVAL;
6559 }
6560
6561 for (i = 0; i < nargs1; i++) {
6562 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6563 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6564
6565 if (t1->info != t2->info) {
6566 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6567 i, fn1, btf_type_str(t1),
6568 fn2, btf_type_str(t2));
6569 return -EINVAL;
6570 }
6571 if (btf_type_has_size(t1) && t1->size != t2->size) {
6572 bpf_log(log,
6573 "arg%d in %s() has size %d while %s() has %d\n",
6574 i, fn1, t1->size,
6575 fn2, t2->size);
6576 return -EINVAL;
6577 }
6578
6579 /* global functions are validated with scalars and pointers
6580 * to context only. And only global functions can be replaced.
6581 * Hence type check only those types.
6582 */
6583 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6584 continue;
6585 if (!btf_type_is_ptr(t1)) {
6586 bpf_log(log,
6587 "arg%d in %s() has unrecognized type\n",
6588 i, fn1);
6589 return -EINVAL;
6590 }
6591 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6592 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6593 if (!btf_type_is_struct(t1)) {
6594 bpf_log(log,
6595 "arg%d in %s() is not a pointer to context\n",
6596 i, fn1);
6597 return -EINVAL;
6598 }
6599 if (!btf_type_is_struct(t2)) {
6600 bpf_log(log,
6601 "arg%d in %s() is not a pointer to context\n",
6602 i, fn2);
6603 return -EINVAL;
6604 }
6605 /* This is an optional check to make program writing easier.
6606 * Compare names of structs and report an error to the user.
6607 * btf_prepare_func_args() already checked that t2 struct
6608 * is a context type. btf_prepare_func_args() will check
6609 * later that t1 struct is a context type as well.
6610 */
6611 s1 = btf_name_by_offset(btf1, t1->name_off);
6612 s2 = btf_name_by_offset(btf2, t2->name_off);
6613 if (strcmp(s1, s2)) {
6614 bpf_log(log,
6615 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6616 i, fn1, s1, fn2, s2);
6617 return -EINVAL;
6618 }
6619 }
6620 return 0;
6621}
6622
6623/* Compare BTFs of given program with BTF of target program */
6624int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
6625 struct btf *btf2, const struct btf_type *t2)
6626{
6627 struct btf *btf1 = prog->aux->btf;
6628 const struct btf_type *t1;
6629 u32 btf_id = 0;
6630
6631 if (!prog->aux->func_info) {
6632 bpf_log(log, "Program extension requires BTF\n");
6633 return -EINVAL;
6634 }
6635
6636 btf_id = prog->aux->func_info[0].type_id;
6637 if (!btf_id)
6638 return -EFAULT;
6639
6640 t1 = btf_type_by_id(btf1, btf_id);
6641 if (!t1 || !btf_type_is_func(t1))
6642 return -EFAULT;
6643
6644 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
6645}
6646
6647static int btf_check_func_arg_match(struct bpf_verifier_env *env,
6648 const struct btf *btf, u32 func_id,
6649 struct bpf_reg_state *regs,
6650 bool ptr_to_mem_ok,
6651 bool processing_call)
6652{
6653 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
6654 struct bpf_verifier_log *log = &env->log;
6655 const char *func_name, *ref_tname;
6656 const struct btf_type *t, *ref_t;
6657 const struct btf_param *args;
6658 u32 i, nargs, ref_id;
6659 int ret;
6660
6661 t = btf_type_by_id(btf, func_id);
6662 if (!t || !btf_type_is_func(t)) {
6663 /* These checks were already done by the verifier while loading
6664 * struct bpf_func_info or in add_kfunc_call().
6665 */
6666 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
6667 func_id);
6668 return -EFAULT;
6669 }
6670 func_name = btf_name_by_offset(btf, t->name_off);
6671
6672 t = btf_type_by_id(btf, t->type);
6673 if (!t || !btf_type_is_func_proto(t)) {
6674 bpf_log(log, "Invalid BTF of func %s\n", func_name);
6675 return -EFAULT;
6676 }
6677 args = (const struct btf_param *)(t + 1);
6678 nargs = btf_type_vlen(t);
6679 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6680 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
6681 MAX_BPF_FUNC_REG_ARGS);
6682 return -EINVAL;
6683 }
6684
6685 /* check that BTF function arguments match actual types that the
6686 * verifier sees.
6687 */
6688 for (i = 0; i < nargs; i++) {
6689 enum bpf_arg_type arg_type = ARG_DONTCARE;
6690 u32 regno = i + 1;
6691 struct bpf_reg_state *reg = ®s[regno];
6692
6693 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6694 if (btf_type_is_scalar(t)) {
6695 if (reg->type == SCALAR_VALUE)
6696 continue;
6697 bpf_log(log, "R%d is not a scalar\n", regno);
6698 return -EINVAL;
6699 }
6700
6701 if (!btf_type_is_ptr(t)) {
6702 bpf_log(log, "Unrecognized arg#%d type %s\n",
6703 i, btf_type_str(t));
6704 return -EINVAL;
6705 }
6706
6707 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
6708 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
6709
6710 ret = check_func_arg_reg_off(env, reg, regno, arg_type);
6711 if (ret < 0)
6712 return ret;
6713
6714 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6715 /* If function expects ctx type in BTF check that caller
6716 * is passing PTR_TO_CTX.
6717 */
6718 if (reg->type != PTR_TO_CTX) {
6719 bpf_log(log,
6720 "arg#%d expected pointer to ctx, but got %s\n",
6721 i, btf_type_str(t));
6722 return -EINVAL;
6723 }
6724 } else if (ptr_to_mem_ok && processing_call) {
6725 const struct btf_type *resolve_ret;
6726 u32 type_size;
6727
6728 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
6729 if (IS_ERR(resolve_ret)) {
6730 bpf_log(log,
6731 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6732 i, btf_type_str(ref_t), ref_tname,
6733 PTR_ERR(resolve_ret));
6734 return -EINVAL;
6735 }
6736
6737 if (check_mem_reg(env, reg, regno, type_size))
6738 return -EINVAL;
6739 } else {
6740 bpf_log(log, "reg type unsupported for arg#%d function %s#%d\n", i,
6741 func_name, func_id);
6742 return -EINVAL;
6743 }
6744 }
6745
6746 return 0;
6747}
6748
6749/* Compare BTF of a function declaration with given bpf_reg_state.
6750 * Returns:
6751 * EFAULT - there is a verifier bug. Abort verification.
6752 * EINVAL - there is a type mismatch or BTF is not available.
6753 * 0 - BTF matches with what bpf_reg_state expects.
6754 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6755 */
6756int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
6757 struct bpf_reg_state *regs)
6758{
6759 struct bpf_prog *prog = env->prog;
6760 struct btf *btf = prog->aux->btf;
6761 bool is_global;
6762 u32 btf_id;
6763 int err;
6764
6765 if (!prog->aux->func_info)
6766 return -EINVAL;
6767
6768 btf_id = prog->aux->func_info[subprog].type_id;
6769 if (!btf_id)
6770 return -EFAULT;
6771
6772 if (prog->aux->func_info_aux[subprog].unreliable)
6773 return -EINVAL;
6774
6775 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6776 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, false);
6777
6778 /* Compiler optimizations can remove arguments from static functions
6779 * or mismatched type can be passed into a global function.
6780 * In such cases mark the function as unreliable from BTF point of view.
6781 */
6782 if (err)
6783 prog->aux->func_info_aux[subprog].unreliable = true;
6784 return err;
6785}
6786
6787/* Compare BTF of a function call with given bpf_reg_state.
6788 * Returns:
6789 * EFAULT - there is a verifier bug. Abort verification.
6790 * EINVAL - there is a type mismatch or BTF is not available.
6791 * 0 - BTF matches with what bpf_reg_state expects.
6792 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6793 *
6794 * NOTE: the code is duplicated from btf_check_subprog_arg_match()
6795 * because btf_check_func_arg_match() is still doing both. Once that
6796 * function is split in 2, we can call from here btf_check_subprog_arg_match()
6797 * first, and then treat the calling part in a new code path.
6798 */
6799int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
6800 struct bpf_reg_state *regs)
6801{
6802 struct bpf_prog *prog = env->prog;
6803 struct btf *btf = prog->aux->btf;
6804 bool is_global;
6805 u32 btf_id;
6806 int err;
6807
6808 if (!prog->aux->func_info)
6809 return -EINVAL;
6810
6811 btf_id = prog->aux->func_info[subprog].type_id;
6812 if (!btf_id)
6813 return -EFAULT;
6814
6815 if (prog->aux->func_info_aux[subprog].unreliable)
6816 return -EINVAL;
6817
6818 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6819 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, true);
6820
6821 /* Compiler optimizations can remove arguments from static functions
6822 * or mismatched type can be passed into a global function.
6823 * In such cases mark the function as unreliable from BTF point of view.
6824 */
6825 if (err)
6826 prog->aux->func_info_aux[subprog].unreliable = true;
6827 return err;
6828}
6829
6830/* Convert BTF of a function into bpf_reg_state if possible
6831 * Returns:
6832 * EFAULT - there is a verifier bug. Abort verification.
6833 * EINVAL - cannot convert BTF.
6834 * 0 - Successfully converted BTF into bpf_reg_state
6835 * (either PTR_TO_CTX or SCALAR_VALUE).
6836 */
6837int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
6838 struct bpf_reg_state *regs)
6839{
6840 struct bpf_verifier_log *log = &env->log;
6841 struct bpf_prog *prog = env->prog;
6842 enum bpf_prog_type prog_type = prog->type;
6843 struct btf *btf = prog->aux->btf;
6844 const struct btf_param *args;
6845 const struct btf_type *t, *ref_t;
6846 u32 i, nargs, btf_id;
6847 const char *tname;
6848
6849 if (!prog->aux->func_info ||
6850 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
6851 bpf_log(log, "Verifier bug\n");
6852 return -EFAULT;
6853 }
6854
6855 btf_id = prog->aux->func_info[subprog].type_id;
6856 if (!btf_id) {
6857 bpf_log(log, "Global functions need valid BTF\n");
6858 return -EFAULT;
6859 }
6860
6861 t = btf_type_by_id(btf, btf_id);
6862 if (!t || !btf_type_is_func(t)) {
6863 /* These checks were already done by the verifier while loading
6864 * struct bpf_func_info
6865 */
6866 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6867 subprog);
6868 return -EFAULT;
6869 }
6870 tname = btf_name_by_offset(btf, t->name_off);
6871
6872 if (log->level & BPF_LOG_LEVEL)
6873 bpf_log(log, "Validating %s() func#%d...\n",
6874 tname, subprog);
6875
6876 if (prog->aux->func_info_aux[subprog].unreliable) {
6877 bpf_log(log, "Verifier bug in function %s()\n", tname);
6878 return -EFAULT;
6879 }
6880 if (prog_type == BPF_PROG_TYPE_EXT)
6881 prog_type = prog->aux->dst_prog->type;
6882
6883 t = btf_type_by_id(btf, t->type);
6884 if (!t || !btf_type_is_func_proto(t)) {
6885 bpf_log(log, "Invalid type of function %s()\n", tname);
6886 return -EFAULT;
6887 }
6888 args = (const struct btf_param *)(t + 1);
6889 nargs = btf_type_vlen(t);
6890 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6891 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
6892 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
6893 return -EINVAL;
6894 }
6895 /* check that function returns int */
6896 t = btf_type_by_id(btf, t->type);
6897 while (btf_type_is_modifier(t))
6898 t = btf_type_by_id(btf, t->type);
6899 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
6900 bpf_log(log,
6901 "Global function %s() doesn't return scalar. Only those are supported.\n",
6902 tname);
6903 return -EINVAL;
6904 }
6905 /* Convert BTF function arguments into verifier types.
6906 * Only PTR_TO_CTX and SCALAR are supported atm.
6907 */
6908 for (i = 0; i < nargs; i++) {
6909 struct bpf_reg_state *reg = ®s[i + 1];
6910
6911 t = btf_type_by_id(btf, args[i].type);
6912 while (btf_type_is_modifier(t))
6913 t = btf_type_by_id(btf, t->type);
6914 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
6915 reg->type = SCALAR_VALUE;
6916 continue;
6917 }
6918 if (btf_type_is_ptr(t)) {
6919 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6920 reg->type = PTR_TO_CTX;
6921 continue;
6922 }
6923
6924 t = btf_type_skip_modifiers(btf, t->type, NULL);
6925
6926 ref_t = btf_resolve_size(btf, t, ®->mem_size);
6927 if (IS_ERR(ref_t)) {
6928 bpf_log(log,
6929 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6930 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
6931 PTR_ERR(ref_t));
6932 return -EINVAL;
6933 }
6934
6935 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
6936 reg->id = ++env->id_gen;
6937
6938 continue;
6939 }
6940 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
6941 i, btf_type_str(t), tname);
6942 return -EINVAL;
6943 }
6944 return 0;
6945}
6946
6947static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
6948 struct btf_show *show)
6949{
6950 const struct btf_type *t = btf_type_by_id(btf, type_id);
6951
6952 show->btf = btf;
6953 memset(&show->state, 0, sizeof(show->state));
6954 memset(&show->obj, 0, sizeof(show->obj));
6955
6956 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
6957}
6958
6959static void btf_seq_show(struct btf_show *show, const char *fmt,
6960 va_list args)
6961{
6962 seq_vprintf((struct seq_file *)show->target, fmt, args);
6963}
6964
6965int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
6966 void *obj, struct seq_file *m, u64 flags)
6967{
6968 struct btf_show sseq;
6969
6970 sseq.target = m;
6971 sseq.showfn = btf_seq_show;
6972 sseq.flags = flags;
6973
6974 btf_type_show(btf, type_id, obj, &sseq);
6975
6976 return sseq.state.status;
6977}
6978
6979void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
6980 struct seq_file *m)
6981{
6982 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
6983 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
6984 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
6985}
6986
6987struct btf_show_snprintf {
6988 struct btf_show show;
6989 int len_left; /* space left in string */
6990 int len; /* length we would have written */
6991};
6992
6993static void btf_snprintf_show(struct btf_show *show, const char *fmt,
6994 va_list args)
6995{
6996 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
6997 int len;
6998
6999 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7000
7001 if (len < 0) {
7002 ssnprintf->len_left = 0;
7003 ssnprintf->len = len;
7004 } else if (len >= ssnprintf->len_left) {
7005 /* no space, drive on to get length we would have written */
7006 ssnprintf->len_left = 0;
7007 ssnprintf->len += len;
7008 } else {
7009 ssnprintf->len_left -= len;
7010 ssnprintf->len += len;
7011 show->target += len;
7012 }
7013}
7014
7015int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7016 char *buf, int len, u64 flags)
7017{
7018 struct btf_show_snprintf ssnprintf;
7019
7020 ssnprintf.show.target = buf;
7021 ssnprintf.show.flags = flags;
7022 ssnprintf.show.showfn = btf_snprintf_show;
7023 ssnprintf.len_left = len;
7024 ssnprintf.len = 0;
7025
7026 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7027
7028 /* If we encountered an error, return it. */
7029 if (ssnprintf.show.state.status)
7030 return ssnprintf.show.state.status;
7031
7032 /* Otherwise return length we would have written */
7033 return ssnprintf.len;
7034}
7035
7036#ifdef CONFIG_PROC_FS
7037static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7038{
7039 const struct btf *btf = filp->private_data;
7040
7041 seq_printf(m, "btf_id:\t%u\n", btf->id);
7042}
7043#endif
7044
7045static int btf_release(struct inode *inode, struct file *filp)
7046{
7047 btf_put(filp->private_data);
7048 return 0;
7049}
7050
7051const struct file_operations btf_fops = {
7052#ifdef CONFIG_PROC_FS
7053 .show_fdinfo = bpf_btf_show_fdinfo,
7054#endif
7055 .release = btf_release,
7056};
7057
7058static int __btf_new_fd(struct btf *btf)
7059{
7060 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7061}
7062
7063int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
7064{
7065 struct btf *btf;
7066 int ret;
7067
7068 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
7069 attr->btf_size, attr->btf_log_level,
7070 u64_to_user_ptr(attr->btf_log_buf),
7071 attr->btf_log_size);
7072 if (IS_ERR(btf))
7073 return PTR_ERR(btf);
7074
7075 ret = btf_alloc_id(btf);
7076 if (ret) {
7077 btf_free(btf);
7078 return ret;
7079 }
7080
7081 /*
7082 * The BTF ID is published to the userspace.
7083 * All BTF free must go through call_rcu() from
7084 * now on (i.e. free by calling btf_put()).
7085 */
7086
7087 ret = __btf_new_fd(btf);
7088 if (ret < 0)
7089 btf_put(btf);
7090
7091 return ret;
7092}
7093
7094struct btf *btf_get_by_fd(int fd)
7095{
7096 struct btf *btf;
7097 struct fd f;
7098
7099 f = fdget(fd);
7100
7101 if (!f.file)
7102 return ERR_PTR(-EBADF);
7103
7104 if (f.file->f_op != &btf_fops) {
7105 fdput(f);
7106 return ERR_PTR(-EINVAL);
7107 }
7108
7109 btf = f.file->private_data;
7110 refcount_inc(&btf->refcnt);
7111 fdput(f);
7112
7113 return btf;
7114}
7115
7116int btf_get_info_by_fd(const struct btf *btf,
7117 const union bpf_attr *attr,
7118 union bpf_attr __user *uattr)
7119{
7120 struct bpf_btf_info __user *uinfo;
7121 struct bpf_btf_info info;
7122 u32 info_copy, btf_copy;
7123 void __user *ubtf;
7124 char __user *uname;
7125 u32 uinfo_len, uname_len, name_len;
7126 int ret = 0;
7127
7128 uinfo = u64_to_user_ptr(attr->info.info);
7129 uinfo_len = attr->info.info_len;
7130
7131 info_copy = min_t(u32, uinfo_len, sizeof(info));
7132 memset(&info, 0, sizeof(info));
7133 if (copy_from_user(&info, uinfo, info_copy))
7134 return -EFAULT;
7135
7136 info.id = btf->id;
7137 ubtf = u64_to_user_ptr(info.btf);
7138 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7139 if (copy_to_user(ubtf, btf->data, btf_copy))
7140 return -EFAULT;
7141 info.btf_size = btf->data_size;
7142
7143 info.kernel_btf = btf->kernel_btf;
7144
7145 uname = u64_to_user_ptr(info.name);
7146 uname_len = info.name_len;
7147 if (!uname ^ !uname_len)
7148 return -EINVAL;
7149
7150 name_len = strlen(btf->name);
7151 info.name_len = name_len;
7152
7153 if (uname) {
7154 if (uname_len >= name_len + 1) {
7155 if (copy_to_user(uname, btf->name, name_len + 1))
7156 return -EFAULT;
7157 } else {
7158 char zero = '\0';
7159
7160 if (copy_to_user(uname, btf->name, uname_len - 1))
7161 return -EFAULT;
7162 if (put_user(zero, uname + uname_len - 1))
7163 return -EFAULT;
7164 /* let user-space know about too short buffer */
7165 ret = -ENOSPC;
7166 }
7167 }
7168
7169 if (copy_to_user(uinfo, &info, info_copy) ||
7170 put_user(info_copy, &uattr->info.info_len))
7171 return -EFAULT;
7172
7173 return ret;
7174}
7175
7176int btf_get_fd_by_id(u32 id)
7177{
7178 struct btf *btf;
7179 int fd;
7180
7181 rcu_read_lock();
7182 btf = idr_find(&btf_idr, id);
7183 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7184 btf = ERR_PTR(-ENOENT);
7185 rcu_read_unlock();
7186
7187 if (IS_ERR(btf))
7188 return PTR_ERR(btf);
7189
7190 fd = __btf_new_fd(btf);
7191 if (fd < 0)
7192 btf_put(btf);
7193
7194 return fd;
7195}
7196
7197u32 btf_obj_id(const struct btf *btf)
7198{
7199 return btf->id;
7200}
7201
7202bool btf_is_kernel(const struct btf *btf)
7203{
7204 return btf->kernel_btf;
7205}
7206
7207bool btf_is_module(const struct btf *btf)
7208{
7209 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7210}
7211
7212enum {
7213 BTF_MODULE_F_LIVE = (1 << 0),
7214};
7215
7216#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7217struct btf_module {
7218 struct list_head list;
7219 struct module *module;
7220 struct btf *btf;
7221 struct bin_attribute *sysfs_attr;
7222 int flags;
7223};
7224
7225static LIST_HEAD(btf_modules);
7226static DEFINE_MUTEX(btf_module_mutex);
7227
7228static ssize_t
7229btf_module_read(struct file *file, struct kobject *kobj,
7230 struct bin_attribute *bin_attr,
7231 char *buf, loff_t off, size_t len)
7232{
7233 const struct btf *btf = bin_attr->private;
7234
7235 memcpy(buf, btf->data + off, len);
7236 return len;
7237}
7238
7239static void purge_cand_cache(struct btf *btf);
7240
7241static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7242 void *module)
7243{
7244 struct btf_module *btf_mod, *tmp;
7245 struct module *mod = module;
7246 struct btf *btf;
7247 int err = 0;
7248
7249 if (mod->btf_data_size == 0 ||
7250 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7251 op != MODULE_STATE_GOING))
7252 goto out;
7253
7254 switch (op) {
7255 case MODULE_STATE_COMING:
7256 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7257 if (!btf_mod) {
7258 err = -ENOMEM;
7259 goto out;
7260 }
7261 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7262 if (IS_ERR(btf)) {
7263 pr_warn("failed to validate module [%s] BTF: %ld\n",
7264 mod->name, PTR_ERR(btf));
7265 kfree(btf_mod);
7266 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
7267 err = PTR_ERR(btf);
7268 goto out;
7269 }
7270 err = btf_alloc_id(btf);
7271 if (err) {
7272 btf_free(btf);
7273 kfree(btf_mod);
7274 goto out;
7275 }
7276
7277 purge_cand_cache(NULL);
7278 mutex_lock(&btf_module_mutex);
7279 btf_mod->module = module;
7280 btf_mod->btf = btf;
7281 list_add(&btf_mod->list, &btf_modules);
7282 mutex_unlock(&btf_module_mutex);
7283
7284 if (IS_ENABLED(CONFIG_SYSFS)) {
7285 struct bin_attribute *attr;
7286
7287 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7288 if (!attr)
7289 goto out;
7290
7291 sysfs_bin_attr_init(attr);
7292 attr->attr.name = btf->name;
7293 attr->attr.mode = 0444;
7294 attr->size = btf->data_size;
7295 attr->private = btf;
7296 attr->read = btf_module_read;
7297
7298 err = sysfs_create_bin_file(btf_kobj, attr);
7299 if (err) {
7300 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7301 mod->name, err);
7302 kfree(attr);
7303 err = 0;
7304 goto out;
7305 }
7306
7307 btf_mod->sysfs_attr = attr;
7308 }
7309
7310 break;
7311 case MODULE_STATE_LIVE:
7312 mutex_lock(&btf_module_mutex);
7313 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7314 if (btf_mod->module != module)
7315 continue;
7316
7317 btf_mod->flags |= BTF_MODULE_F_LIVE;
7318 break;
7319 }
7320 mutex_unlock(&btf_module_mutex);
7321 break;
7322 case MODULE_STATE_GOING:
7323 mutex_lock(&btf_module_mutex);
7324 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7325 if (btf_mod->module != module)
7326 continue;
7327
7328 list_del(&btf_mod->list);
7329 if (btf_mod->sysfs_attr)
7330 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7331 purge_cand_cache(btf_mod->btf);
7332 btf_put(btf_mod->btf);
7333 kfree(btf_mod->sysfs_attr);
7334 kfree(btf_mod);
7335 break;
7336 }
7337 mutex_unlock(&btf_module_mutex);
7338 break;
7339 }
7340out:
7341 return notifier_from_errno(err);
7342}
7343
7344static struct notifier_block btf_module_nb = {
7345 .notifier_call = btf_module_notify,
7346};
7347
7348static int __init btf_module_init(void)
7349{
7350 register_module_notifier(&btf_module_nb);
7351 return 0;
7352}
7353
7354fs_initcall(btf_module_init);
7355#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7356
7357struct module *btf_try_get_module(const struct btf *btf)
7358{
7359 struct module *res = NULL;
7360#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7361 struct btf_module *btf_mod, *tmp;
7362
7363 mutex_lock(&btf_module_mutex);
7364 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7365 if (btf_mod->btf != btf)
7366 continue;
7367
7368 /* We must only consider module whose __init routine has
7369 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7370 * which is set from the notifier callback for
7371 * MODULE_STATE_LIVE.
7372 */
7373 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7374 res = btf_mod->module;
7375
7376 break;
7377 }
7378 mutex_unlock(&btf_module_mutex);
7379#endif
7380
7381 return res;
7382}
7383
7384/* Returns struct btf corresponding to the struct module.
7385 * This function can return NULL or ERR_PTR.
7386 */
7387static struct btf *btf_get_module_btf(const struct module *module)
7388{
7389#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7390 struct btf_module *btf_mod, *tmp;
7391#endif
7392 struct btf *btf = NULL;
7393
7394 if (!module) {
7395 btf = bpf_get_btf_vmlinux();
7396 if (!IS_ERR_OR_NULL(btf))
7397 btf_get(btf);
7398 return btf;
7399 }
7400
7401#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7402 mutex_lock(&btf_module_mutex);
7403 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7404 if (btf_mod->module != module)
7405 continue;
7406
7407 btf_get(btf_mod->btf);
7408 btf = btf_mod->btf;
7409 break;
7410 }
7411 mutex_unlock(&btf_module_mutex);
7412#endif
7413
7414 return btf;
7415}
7416
7417BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7418{
7419 struct btf *btf = NULL;
7420 int btf_obj_fd = 0;
7421 long ret;
7422
7423 if (flags)
7424 return -EINVAL;
7425
7426 if (name_sz <= 1 || name[name_sz - 1])
7427 return -EINVAL;
7428
7429 ret = bpf_find_btf_id(name, kind, &btf);
7430 if (ret > 0 && btf_is_module(btf)) {
7431 btf_obj_fd = __btf_new_fd(btf);
7432 if (btf_obj_fd < 0) {
7433 btf_put(btf);
7434 return btf_obj_fd;
7435 }
7436 return ret | (((u64)btf_obj_fd) << 32);
7437 }
7438 if (ret > 0)
7439 btf_put(btf);
7440 return ret;
7441}
7442
7443const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7444 .func = bpf_btf_find_by_name_kind,
7445 .gpl_only = false,
7446 .ret_type = RET_INTEGER,
7447 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
7448 .arg2_type = ARG_CONST_SIZE,
7449 .arg3_type = ARG_ANYTHING,
7450 .arg4_type = ARG_ANYTHING,
7451};
7452
7453BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7454#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7455BTF_TRACING_TYPE_xxx
7456#undef BTF_TRACING_TYPE
7457
7458/* Kernel Function (kfunc) BTF ID set registration API */
7459
7460static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7461 struct btf_id_set8 *add_set)
7462{
7463 bool vmlinux_set = !btf_is_module(btf);
7464 struct btf_kfunc_set_tab *tab;
7465 struct btf_id_set8 *set;
7466 u32 set_cnt;
7467 int ret;
7468
7469 if (hook >= BTF_KFUNC_HOOK_MAX) {
7470 ret = -EINVAL;
7471 goto end;
7472 }
7473
7474 if (!add_set->cnt)
7475 return 0;
7476
7477 tab = btf->kfunc_set_tab;
7478 if (!tab) {
7479 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
7480 if (!tab)
7481 return -ENOMEM;
7482 btf->kfunc_set_tab = tab;
7483 }
7484
7485 set = tab->sets[hook];
7486 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
7487 * for module sets.
7488 */
7489 if (WARN_ON_ONCE(set && !vmlinux_set)) {
7490 ret = -EINVAL;
7491 goto end;
7492 }
7493
7494 /* We don't need to allocate, concatenate, and sort module sets, because
7495 * only one is allowed per hook. Hence, we can directly assign the
7496 * pointer and return.
7497 */
7498 if (!vmlinux_set) {
7499 tab->sets[hook] = add_set;
7500 return 0;
7501 }
7502
7503 /* In case of vmlinux sets, there may be more than one set being
7504 * registered per hook. To create a unified set, we allocate a new set
7505 * and concatenate all individual sets being registered. While each set
7506 * is individually sorted, they may become unsorted when concatenated,
7507 * hence re-sorting the final set again is required to make binary
7508 * searching the set using btf_id_set8_contains function work.
7509 */
7510 set_cnt = set ? set->cnt : 0;
7511
7512 if (set_cnt > U32_MAX - add_set->cnt) {
7513 ret = -EOVERFLOW;
7514 goto end;
7515 }
7516
7517 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
7518 ret = -E2BIG;
7519 goto end;
7520 }
7521
7522 /* Grow set */
7523 set = krealloc(tab->sets[hook],
7524 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
7525 GFP_KERNEL | __GFP_NOWARN);
7526 if (!set) {
7527 ret = -ENOMEM;
7528 goto end;
7529 }
7530
7531 /* For newly allocated set, initialize set->cnt to 0 */
7532 if (!tab->sets[hook])
7533 set->cnt = 0;
7534 tab->sets[hook] = set;
7535
7536 /* Concatenate the two sets */
7537 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
7538 set->cnt += add_set->cnt;
7539
7540 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
7541
7542 return 0;
7543end:
7544 btf_free_kfunc_set_tab(btf);
7545 return ret;
7546}
7547
7548static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
7549 enum btf_kfunc_hook hook,
7550 u32 kfunc_btf_id)
7551{
7552 struct btf_id_set8 *set;
7553 u32 *id;
7554
7555 if (hook >= BTF_KFUNC_HOOK_MAX)
7556 return NULL;
7557 if (!btf->kfunc_set_tab)
7558 return NULL;
7559 set = btf->kfunc_set_tab->sets[hook];
7560 if (!set)
7561 return NULL;
7562 id = btf_id_set8_contains(set, kfunc_btf_id);
7563 if (!id)
7564 return NULL;
7565 /* The flags for BTF ID are located next to it */
7566 return id + 1;
7567}
7568
7569static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7570{
7571 switch (prog_type) {
7572 case BPF_PROG_TYPE_UNSPEC:
7573 return BTF_KFUNC_HOOK_COMMON;
7574 case BPF_PROG_TYPE_XDP:
7575 return BTF_KFUNC_HOOK_XDP;
7576 case BPF_PROG_TYPE_SCHED_CLS:
7577 return BTF_KFUNC_HOOK_TC;
7578 case BPF_PROG_TYPE_STRUCT_OPS:
7579 return BTF_KFUNC_HOOK_STRUCT_OPS;
7580 case BPF_PROG_TYPE_TRACING:
7581 case BPF_PROG_TYPE_LSM:
7582 return BTF_KFUNC_HOOK_TRACING;
7583 case BPF_PROG_TYPE_SYSCALL:
7584 return BTF_KFUNC_HOOK_SYSCALL;
7585 default:
7586 return BTF_KFUNC_HOOK_MAX;
7587 }
7588}
7589
7590/* Caution:
7591 * Reference to the module (obtained using btf_try_get_module) corresponding to
7592 * the struct btf *MUST* be held when calling this function from verifier
7593 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7594 * keeping the reference for the duration of the call provides the necessary
7595 * protection for looking up a well-formed btf->kfunc_set_tab.
7596 */
7597u32 *btf_kfunc_id_set_contains(const struct btf *btf,
7598 enum bpf_prog_type prog_type,
7599 u32 kfunc_btf_id)
7600{
7601 enum btf_kfunc_hook hook;
7602 u32 *kfunc_flags;
7603
7604 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id);
7605 if (kfunc_flags)
7606 return kfunc_flags;
7607
7608 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7609 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
7610}
7611
7612u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id)
7613{
7614 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id);
7615}
7616
7617static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
7618 const struct btf_kfunc_id_set *kset)
7619{
7620 struct btf *btf;
7621 int ret;
7622
7623 btf = btf_get_module_btf(kset->owner);
7624 if (!btf) {
7625 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7626 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7627 return -ENOENT;
7628 }
7629 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7630 pr_err("missing module BTF, cannot register kfuncs\n");
7631 return -ENOENT;
7632 }
7633 return 0;
7634 }
7635 if (IS_ERR(btf))
7636 return PTR_ERR(btf);
7637
7638 ret = btf_populate_kfunc_set(btf, hook, kset->set);
7639 btf_put(btf);
7640 return ret;
7641}
7642
7643/* This function must be invoked only from initcalls/module init functions */
7644int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7645 const struct btf_kfunc_id_set *kset)
7646{
7647 enum btf_kfunc_hook hook;
7648
7649 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7650 return __register_btf_kfunc_id_set(hook, kset);
7651}
7652EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7653
7654/* This function must be invoked only from initcalls/module init functions */
7655int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
7656{
7657 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
7658}
7659EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
7660
7661s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
7662{
7663 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
7664 struct btf_id_dtor_kfunc *dtor;
7665
7666 if (!tab)
7667 return -ENOENT;
7668 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
7669 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
7670 */
7671 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
7672 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
7673 if (!dtor)
7674 return -ENOENT;
7675 return dtor->kfunc_btf_id;
7676}
7677
7678static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
7679{
7680 const struct btf_type *dtor_func, *dtor_func_proto, *t;
7681 const struct btf_param *args;
7682 s32 dtor_btf_id;
7683 u32 nr_args, i;
7684
7685 for (i = 0; i < cnt; i++) {
7686 dtor_btf_id = dtors[i].kfunc_btf_id;
7687
7688 dtor_func = btf_type_by_id(btf, dtor_btf_id);
7689 if (!dtor_func || !btf_type_is_func(dtor_func))
7690 return -EINVAL;
7691
7692 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
7693 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
7694 return -EINVAL;
7695
7696 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
7697 t = btf_type_by_id(btf, dtor_func_proto->type);
7698 if (!t || !btf_type_is_void(t))
7699 return -EINVAL;
7700
7701 nr_args = btf_type_vlen(dtor_func_proto);
7702 if (nr_args != 1)
7703 return -EINVAL;
7704 args = btf_params(dtor_func_proto);
7705 t = btf_type_by_id(btf, args[0].type);
7706 /* Allow any pointer type, as width on targets Linux supports
7707 * will be same for all pointer types (i.e. sizeof(void *))
7708 */
7709 if (!t || !btf_type_is_ptr(t))
7710 return -EINVAL;
7711 }
7712 return 0;
7713}
7714
7715/* This function must be invoked only from initcalls/module init functions */
7716int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
7717 struct module *owner)
7718{
7719 struct btf_id_dtor_kfunc_tab *tab;
7720 struct btf *btf;
7721 u32 tab_cnt;
7722 int ret;
7723
7724 btf = btf_get_module_btf(owner);
7725 if (!btf) {
7726 if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7727 pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
7728 return -ENOENT;
7729 }
7730 if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7731 pr_err("missing module BTF, cannot register dtor kfuncs\n");
7732 return -ENOENT;
7733 }
7734 return 0;
7735 }
7736 if (IS_ERR(btf))
7737 return PTR_ERR(btf);
7738
7739 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7740 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7741 ret = -E2BIG;
7742 goto end;
7743 }
7744
7745 /* Ensure that the prototype of dtor kfuncs being registered is sane */
7746 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
7747 if (ret < 0)
7748 goto end;
7749
7750 tab = btf->dtor_kfunc_tab;
7751 /* Only one call allowed for modules */
7752 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
7753 ret = -EINVAL;
7754 goto end;
7755 }
7756
7757 tab_cnt = tab ? tab->cnt : 0;
7758 if (tab_cnt > U32_MAX - add_cnt) {
7759 ret = -EOVERFLOW;
7760 goto end;
7761 }
7762 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7763 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7764 ret = -E2BIG;
7765 goto end;
7766 }
7767
7768 tab = krealloc(btf->dtor_kfunc_tab,
7769 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
7770 GFP_KERNEL | __GFP_NOWARN);
7771 if (!tab) {
7772 ret = -ENOMEM;
7773 goto end;
7774 }
7775
7776 if (!btf->dtor_kfunc_tab)
7777 tab->cnt = 0;
7778 btf->dtor_kfunc_tab = tab;
7779
7780 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
7781 tab->cnt += add_cnt;
7782
7783 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
7784
7785end:
7786 if (ret)
7787 btf_free_dtor_kfunc_tab(btf);
7788 btf_put(btf);
7789 return ret;
7790}
7791EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
7792
7793#define MAX_TYPES_ARE_COMPAT_DEPTH 2
7794
7795/* Check local and target types for compatibility. This check is used for
7796 * type-based CO-RE relocations and follow slightly different rules than
7797 * field-based relocations. This function assumes that root types were already
7798 * checked for name match. Beyond that initial root-level name check, names
7799 * are completely ignored. Compatibility rules are as follows:
7800 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
7801 * kind should match for local and target types (i.e., STRUCT is not
7802 * compatible with UNION);
7803 * - for ENUMs/ENUM64s, the size is ignored;
7804 * - for INT, size and signedness are ignored;
7805 * - for ARRAY, dimensionality is ignored, element types are checked for
7806 * compatibility recursively;
7807 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
7808 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
7809 * - FUNC_PROTOs are compatible if they have compatible signature: same
7810 * number of input args and compatible return and argument types.
7811 * These rules are not set in stone and probably will be adjusted as we get
7812 * more experience with using BPF CO-RE relocations.
7813 */
7814int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
7815 const struct btf *targ_btf, __u32 targ_id)
7816{
7817 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
7818 MAX_TYPES_ARE_COMPAT_DEPTH);
7819}
7820
7821#define MAX_TYPES_MATCH_DEPTH 2
7822
7823int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
7824 const struct btf *targ_btf, u32 targ_id)
7825{
7826 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
7827 MAX_TYPES_MATCH_DEPTH);
7828}
7829
7830static bool bpf_core_is_flavor_sep(const char *s)
7831{
7832 /* check X___Y name pattern, where X and Y are not underscores */
7833 return s[0] != '_' && /* X */
7834 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
7835 s[4] != '_'; /* Y */
7836}
7837
7838size_t bpf_core_essential_name_len(const char *name)
7839{
7840 size_t n = strlen(name);
7841 int i;
7842
7843 for (i = n - 5; i >= 0; i--) {
7844 if (bpf_core_is_flavor_sep(name + i))
7845 return i + 1;
7846 }
7847 return n;
7848}
7849
7850struct bpf_cand_cache {
7851 const char *name;
7852 u32 name_len;
7853 u16 kind;
7854 u16 cnt;
7855 struct {
7856 const struct btf *btf;
7857 u32 id;
7858 } cands[];
7859};
7860
7861static void bpf_free_cands(struct bpf_cand_cache *cands)
7862{
7863 if (!cands->cnt)
7864 /* empty candidate array was allocated on stack */
7865 return;
7866 kfree(cands);
7867}
7868
7869static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
7870{
7871 kfree(cands->name);
7872 kfree(cands);
7873}
7874
7875#define VMLINUX_CAND_CACHE_SIZE 31
7876static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
7877
7878#define MODULE_CAND_CACHE_SIZE 31
7879static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
7880
7881static DEFINE_MUTEX(cand_cache_mutex);
7882
7883static void __print_cand_cache(struct bpf_verifier_log *log,
7884 struct bpf_cand_cache **cache,
7885 int cache_size)
7886{
7887 struct bpf_cand_cache *cc;
7888 int i, j;
7889
7890 for (i = 0; i < cache_size; i++) {
7891 cc = cache[i];
7892 if (!cc)
7893 continue;
7894 bpf_log(log, "[%d]%s(", i, cc->name);
7895 for (j = 0; j < cc->cnt; j++) {
7896 bpf_log(log, "%d", cc->cands[j].id);
7897 if (j < cc->cnt - 1)
7898 bpf_log(log, " ");
7899 }
7900 bpf_log(log, "), ");
7901 }
7902}
7903
7904static void print_cand_cache(struct bpf_verifier_log *log)
7905{
7906 mutex_lock(&cand_cache_mutex);
7907 bpf_log(log, "vmlinux_cand_cache:");
7908 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7909 bpf_log(log, "\nmodule_cand_cache:");
7910 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7911 bpf_log(log, "\n");
7912 mutex_unlock(&cand_cache_mutex);
7913}
7914
7915static u32 hash_cands(struct bpf_cand_cache *cands)
7916{
7917 return jhash(cands->name, cands->name_len, 0);
7918}
7919
7920static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
7921 struct bpf_cand_cache **cache,
7922 int cache_size)
7923{
7924 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
7925
7926 if (cc && cc->name_len == cands->name_len &&
7927 !strncmp(cc->name, cands->name, cands->name_len))
7928 return cc;
7929 return NULL;
7930}
7931
7932static size_t sizeof_cands(int cnt)
7933{
7934 return offsetof(struct bpf_cand_cache, cands[cnt]);
7935}
7936
7937static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
7938 struct bpf_cand_cache **cache,
7939 int cache_size)
7940{
7941 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
7942
7943 if (*cc) {
7944 bpf_free_cands_from_cache(*cc);
7945 *cc = NULL;
7946 }
7947 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
7948 if (!new_cands) {
7949 bpf_free_cands(cands);
7950 return ERR_PTR(-ENOMEM);
7951 }
7952 /* strdup the name, since it will stay in cache.
7953 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
7954 */
7955 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
7956 bpf_free_cands(cands);
7957 if (!new_cands->name) {
7958 kfree(new_cands);
7959 return ERR_PTR(-ENOMEM);
7960 }
7961 *cc = new_cands;
7962 return new_cands;
7963}
7964
7965#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7966static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
7967 int cache_size)
7968{
7969 struct bpf_cand_cache *cc;
7970 int i, j;
7971
7972 for (i = 0; i < cache_size; i++) {
7973 cc = cache[i];
7974 if (!cc)
7975 continue;
7976 if (!btf) {
7977 /* when new module is loaded purge all of module_cand_cache,
7978 * since new module might have candidates with the name
7979 * that matches cached cands.
7980 */
7981 bpf_free_cands_from_cache(cc);
7982 cache[i] = NULL;
7983 continue;
7984 }
7985 /* when module is unloaded purge cache entries
7986 * that match module's btf
7987 */
7988 for (j = 0; j < cc->cnt; j++)
7989 if (cc->cands[j].btf == btf) {
7990 bpf_free_cands_from_cache(cc);
7991 cache[i] = NULL;
7992 break;
7993 }
7994 }
7995
7996}
7997
7998static void purge_cand_cache(struct btf *btf)
7999{
8000 mutex_lock(&cand_cache_mutex);
8001 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8002 mutex_unlock(&cand_cache_mutex);
8003}
8004#endif
8005
8006static struct bpf_cand_cache *
8007bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8008 int targ_start_id)
8009{
8010 struct bpf_cand_cache *new_cands;
8011 const struct btf_type *t;
8012 const char *targ_name;
8013 size_t targ_essent_len;
8014 int n, i;
8015
8016 n = btf_nr_types(targ_btf);
8017 for (i = targ_start_id; i < n; i++) {
8018 t = btf_type_by_id(targ_btf, i);
8019 if (btf_kind(t) != cands->kind)
8020 continue;
8021
8022 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8023 if (!targ_name)
8024 continue;
8025
8026 /* the resched point is before strncmp to make sure that search
8027 * for non-existing name will have a chance to schedule().
8028 */
8029 cond_resched();
8030
8031 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8032 continue;
8033
8034 targ_essent_len = bpf_core_essential_name_len(targ_name);
8035 if (targ_essent_len != cands->name_len)
8036 continue;
8037
8038 /* most of the time there is only one candidate for a given kind+name pair */
8039 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8040 if (!new_cands) {
8041 bpf_free_cands(cands);
8042 return ERR_PTR(-ENOMEM);
8043 }
8044
8045 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8046 bpf_free_cands(cands);
8047 cands = new_cands;
8048 cands->cands[cands->cnt].btf = targ_btf;
8049 cands->cands[cands->cnt].id = i;
8050 cands->cnt++;
8051 }
8052 return cands;
8053}
8054
8055static struct bpf_cand_cache *
8056bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8057{
8058 struct bpf_cand_cache *cands, *cc, local_cand = {};
8059 const struct btf *local_btf = ctx->btf;
8060 const struct btf_type *local_type;
8061 const struct btf *main_btf;
8062 size_t local_essent_len;
8063 struct btf *mod_btf;
8064 const char *name;
8065 int id;
8066
8067 main_btf = bpf_get_btf_vmlinux();
8068 if (IS_ERR(main_btf))
8069 return ERR_CAST(main_btf);
8070 if (!main_btf)
8071 return ERR_PTR(-EINVAL);
8072
8073 local_type = btf_type_by_id(local_btf, local_type_id);
8074 if (!local_type)
8075 return ERR_PTR(-EINVAL);
8076
8077 name = btf_name_by_offset(local_btf, local_type->name_off);
8078 if (str_is_empty(name))
8079 return ERR_PTR(-EINVAL);
8080 local_essent_len = bpf_core_essential_name_len(name);
8081
8082 cands = &local_cand;
8083 cands->name = name;
8084 cands->kind = btf_kind(local_type);
8085 cands->name_len = local_essent_len;
8086
8087 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8088 /* cands is a pointer to stack here */
8089 if (cc) {
8090 if (cc->cnt)
8091 return cc;
8092 goto check_modules;
8093 }
8094
8095 /* Attempt to find target candidates in vmlinux BTF first */
8096 cands = bpf_core_add_cands(cands, main_btf, 1);
8097 if (IS_ERR(cands))
8098 return ERR_CAST(cands);
8099
8100 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8101
8102 /* populate cache even when cands->cnt == 0 */
8103 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8104 if (IS_ERR(cc))
8105 return ERR_CAST(cc);
8106
8107 /* if vmlinux BTF has any candidate, don't go for module BTFs */
8108 if (cc->cnt)
8109 return cc;
8110
8111check_modules:
8112 /* cands is a pointer to stack here and cands->cnt == 0 */
8113 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8114 if (cc)
8115 /* if cache has it return it even if cc->cnt == 0 */
8116 return cc;
8117
8118 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8119 spin_lock_bh(&btf_idr_lock);
8120 idr_for_each_entry(&btf_idr, mod_btf, id) {
8121 if (!btf_is_module(mod_btf))
8122 continue;
8123 /* linear search could be slow hence unlock/lock
8124 * the IDR to avoiding holding it for too long
8125 */
8126 btf_get(mod_btf);
8127 spin_unlock_bh(&btf_idr_lock);
8128 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8129 if (IS_ERR(cands)) {
8130 btf_put(mod_btf);
8131 return ERR_CAST(cands);
8132 }
8133 spin_lock_bh(&btf_idr_lock);
8134 btf_put(mod_btf);
8135 }
8136 spin_unlock_bh(&btf_idr_lock);
8137 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
8138 * or pointer to stack if cands->cnd == 0.
8139 * Copy it into the cache even when cands->cnt == 0 and
8140 * return the result.
8141 */
8142 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8143}
8144
8145int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8146 int relo_idx, void *insn)
8147{
8148 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8149 struct bpf_core_cand_list cands = {};
8150 struct bpf_core_relo_res targ_res;
8151 struct bpf_core_spec *specs;
8152 int err;
8153
8154 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8155 * into arrays of btf_ids of struct fields and array indices.
8156 */
8157 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8158 if (!specs)
8159 return -ENOMEM;
8160
8161 if (need_cands) {
8162 struct bpf_cand_cache *cc;
8163 int i;
8164
8165 mutex_lock(&cand_cache_mutex);
8166 cc = bpf_core_find_cands(ctx, relo->type_id);
8167 if (IS_ERR(cc)) {
8168 bpf_log(ctx->log, "target candidate search failed for %d\n",
8169 relo->type_id);
8170 err = PTR_ERR(cc);
8171 goto out;
8172 }
8173 if (cc->cnt) {
8174 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8175 if (!cands.cands) {
8176 err = -ENOMEM;
8177 goto out;
8178 }
8179 }
8180 for (i = 0; i < cc->cnt; i++) {
8181 bpf_log(ctx->log,
8182 "CO-RE relocating %s %s: found target candidate [%d]\n",
8183 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8184 cands.cands[i].btf = cc->cands[i].btf;
8185 cands.cands[i].id = cc->cands[i].id;
8186 }
8187 cands.len = cc->cnt;
8188 /* cand_cache_mutex needs to span the cache lookup and
8189 * copy of btf pointer into bpf_core_cand_list,
8190 * since module can be unloaded while bpf_core_calc_relo_insn
8191 * is working with module's btf.
8192 */
8193 }
8194
8195 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8196 &targ_res);
8197 if (err)
8198 goto out;
8199
8200 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8201 &targ_res);
8202
8203out:
8204 kfree(specs);
8205 if (need_cands) {
8206 kfree(cands.cands);
8207 mutex_unlock(&cand_cache_mutex);
8208 if (ctx->log->level & BPF_LOG_LEVEL2)
8209 print_cand_cache(ctx->log);
8210 }
8211 return err;
8212}
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/bpf.h>
23#include <linux/bpf_lsm.h>
24#include <linux/skmsg.h>
25#include <linux/perf_event.h>
26#include <linux/bsearch.h>
27#include <linux/kobject.h>
28#include <linux/sysfs.h>
29
30#include <net/netfilter/nf_bpf_link.h>
31
32#include <net/sock.h>
33#include <net/xdp.h>
34#include "../tools/lib/bpf/relo_core.h"
35
36/* BTF (BPF Type Format) is the meta data format which describes
37 * the data types of BPF program/map. Hence, it basically focus
38 * on the C programming language which the modern BPF is primary
39 * using.
40 *
41 * ELF Section:
42 * ~~~~~~~~~~~
43 * The BTF data is stored under the ".BTF" ELF section
44 *
45 * struct btf_type:
46 * ~~~~~~~~~~~~~~~
47 * Each 'struct btf_type' object describes a C data type.
48 * Depending on the type it is describing, a 'struct btf_type'
49 * object may be followed by more data. F.e.
50 * To describe an array, 'struct btf_type' is followed by
51 * 'struct btf_array'.
52 *
53 * 'struct btf_type' and any extra data following it are
54 * 4 bytes aligned.
55 *
56 * Type section:
57 * ~~~~~~~~~~~~~
58 * The BTF type section contains a list of 'struct btf_type' objects.
59 * Each one describes a C type. Recall from the above section
60 * that a 'struct btf_type' object could be immediately followed by extra
61 * data in order to describe some particular C types.
62 *
63 * type_id:
64 * ~~~~~~~
65 * Each btf_type object is identified by a type_id. The type_id
66 * is implicitly implied by the location of the btf_type object in
67 * the BTF type section. The first one has type_id 1. The second
68 * one has type_id 2...etc. Hence, an earlier btf_type has
69 * a smaller type_id.
70 *
71 * A btf_type object may refer to another btf_type object by using
72 * type_id (i.e. the "type" in the "struct btf_type").
73 *
74 * NOTE that we cannot assume any reference-order.
75 * A btf_type object can refer to an earlier btf_type object
76 * but it can also refer to a later btf_type object.
77 *
78 * For example, to describe "const void *". A btf_type
79 * object describing "const" may refer to another btf_type
80 * object describing "void *". This type-reference is done
81 * by specifying type_id:
82 *
83 * [1] CONST (anon) type_id=2
84 * [2] PTR (anon) type_id=0
85 *
86 * The above is the btf_verifier debug log:
87 * - Each line started with "[?]" is a btf_type object
88 * - [?] is the type_id of the btf_type object.
89 * - CONST/PTR is the BTF_KIND_XXX
90 * - "(anon)" is the name of the type. It just
91 * happens that CONST and PTR has no name.
92 * - type_id=XXX is the 'u32 type' in btf_type
93 *
94 * NOTE: "void" has type_id 0
95 *
96 * String section:
97 * ~~~~~~~~~~~~~~
98 * The BTF string section contains the names used by the type section.
99 * Each string is referred by an "offset" from the beginning of the
100 * string section.
101 *
102 * Each string is '\0' terminated.
103 *
104 * The first character in the string section must be '\0'
105 * which is used to mean 'anonymous'. Some btf_type may not
106 * have a name.
107 */
108
109/* BTF verification:
110 *
111 * To verify BTF data, two passes are needed.
112 *
113 * Pass #1
114 * ~~~~~~~
115 * The first pass is to collect all btf_type objects to
116 * an array: "btf->types".
117 *
118 * Depending on the C type that a btf_type is describing,
119 * a btf_type may be followed by extra data. We don't know
120 * how many btf_type is there, and more importantly we don't
121 * know where each btf_type is located in the type section.
122 *
123 * Without knowing the location of each type_id, most verifications
124 * cannot be done. e.g. an earlier btf_type may refer to a later
125 * btf_type (recall the "const void *" above), so we cannot
126 * check this type-reference in the first pass.
127 *
128 * In the first pass, it still does some verifications (e.g.
129 * checking the name is a valid offset to the string section).
130 *
131 * Pass #2
132 * ~~~~~~~
133 * The main focus is to resolve a btf_type that is referring
134 * to another type.
135 *
136 * We have to ensure the referring type:
137 * 1) does exist in the BTF (i.e. in btf->types[])
138 * 2) does not cause a loop:
139 * struct A {
140 * struct B b;
141 * };
142 *
143 * struct B {
144 * struct A a;
145 * };
146 *
147 * btf_type_needs_resolve() decides if a btf_type needs
148 * to be resolved.
149 *
150 * The needs_resolve type implements the "resolve()" ops which
151 * essentially does a DFS and detects backedge.
152 *
153 * During resolve (or DFS), different C types have different
154 * "RESOLVED" conditions.
155 *
156 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
157 * members because a member is always referring to another
158 * type. A struct's member can be treated as "RESOLVED" if
159 * it is referring to a BTF_KIND_PTR. Otherwise, the
160 * following valid C struct would be rejected:
161 *
162 * struct A {
163 * int m;
164 * struct A *a;
165 * };
166 *
167 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
168 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
169 * detect a pointer loop, e.g.:
170 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
171 * ^ |
172 * +-----------------------------------------+
173 *
174 */
175
176#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
177#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
178#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
179#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
180#define BITS_ROUNDUP_BYTES(bits) \
181 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
182
183#define BTF_INFO_MASK 0x9f00ffff
184#define BTF_INT_MASK 0x0fffffff
185#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
186#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
187
188/* 16MB for 64k structs and each has 16 members and
189 * a few MB spaces for the string section.
190 * The hard limit is S32_MAX.
191 */
192#define BTF_MAX_SIZE (16 * 1024 * 1024)
193
194#define for_each_member_from(i, from, struct_type, member) \
195 for (i = from, member = btf_type_member(struct_type) + from; \
196 i < btf_type_vlen(struct_type); \
197 i++, member++)
198
199#define for_each_vsi_from(i, from, struct_type, member) \
200 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
201 i < btf_type_vlen(struct_type); \
202 i++, member++)
203
204DEFINE_IDR(btf_idr);
205DEFINE_SPINLOCK(btf_idr_lock);
206
207enum btf_kfunc_hook {
208 BTF_KFUNC_HOOK_COMMON,
209 BTF_KFUNC_HOOK_XDP,
210 BTF_KFUNC_HOOK_TC,
211 BTF_KFUNC_HOOK_STRUCT_OPS,
212 BTF_KFUNC_HOOK_TRACING,
213 BTF_KFUNC_HOOK_SYSCALL,
214 BTF_KFUNC_HOOK_FMODRET,
215 BTF_KFUNC_HOOK_CGROUP,
216 BTF_KFUNC_HOOK_SCHED_ACT,
217 BTF_KFUNC_HOOK_SK_SKB,
218 BTF_KFUNC_HOOK_SOCKET_FILTER,
219 BTF_KFUNC_HOOK_LWT,
220 BTF_KFUNC_HOOK_NETFILTER,
221 BTF_KFUNC_HOOK_KPROBE,
222 BTF_KFUNC_HOOK_MAX,
223};
224
225enum {
226 BTF_KFUNC_SET_MAX_CNT = 256,
227 BTF_DTOR_KFUNC_MAX_CNT = 256,
228 BTF_KFUNC_FILTER_MAX_CNT = 16,
229};
230
231struct btf_kfunc_hook_filter {
232 btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
233 u32 nr_filters;
234};
235
236struct btf_kfunc_set_tab {
237 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
238 struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
239};
240
241struct btf_id_dtor_kfunc_tab {
242 u32 cnt;
243 struct btf_id_dtor_kfunc dtors[];
244};
245
246struct btf_struct_ops_tab {
247 u32 cnt;
248 u32 capacity;
249 struct bpf_struct_ops_desc ops[];
250};
251
252struct btf {
253 void *data;
254 struct btf_type **types;
255 u32 *resolved_ids;
256 u32 *resolved_sizes;
257 const char *strings;
258 void *nohdr_data;
259 struct btf_header hdr;
260 u32 nr_types; /* includes VOID for base BTF */
261 u32 types_size;
262 u32 data_size;
263 refcount_t refcnt;
264 u32 id;
265 struct rcu_head rcu;
266 struct btf_kfunc_set_tab *kfunc_set_tab;
267 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
268 struct btf_struct_metas *struct_meta_tab;
269 struct btf_struct_ops_tab *struct_ops_tab;
270
271 /* split BTF support */
272 struct btf *base_btf;
273 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
274 u32 start_str_off; /* first string offset (0 for base BTF) */
275 char name[MODULE_NAME_LEN];
276 bool kernel_btf;
277 __u32 *base_id_map; /* map from distilled base BTF -> vmlinux BTF ids */
278};
279
280enum verifier_phase {
281 CHECK_META,
282 CHECK_TYPE,
283};
284
285struct resolve_vertex {
286 const struct btf_type *t;
287 u32 type_id;
288 u16 next_member;
289};
290
291enum visit_state {
292 NOT_VISITED,
293 VISITED,
294 RESOLVED,
295};
296
297enum resolve_mode {
298 RESOLVE_TBD, /* To Be Determined */
299 RESOLVE_PTR, /* Resolving for Pointer */
300 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
301 * or array
302 */
303};
304
305#define MAX_RESOLVE_DEPTH 32
306
307struct btf_sec_info {
308 u32 off;
309 u32 len;
310};
311
312struct btf_verifier_env {
313 struct btf *btf;
314 u8 *visit_states;
315 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
316 struct bpf_verifier_log log;
317 u32 log_type_id;
318 u32 top_stack;
319 enum verifier_phase phase;
320 enum resolve_mode resolve_mode;
321};
322
323static const char * const btf_kind_str[NR_BTF_KINDS] = {
324 [BTF_KIND_UNKN] = "UNKNOWN",
325 [BTF_KIND_INT] = "INT",
326 [BTF_KIND_PTR] = "PTR",
327 [BTF_KIND_ARRAY] = "ARRAY",
328 [BTF_KIND_STRUCT] = "STRUCT",
329 [BTF_KIND_UNION] = "UNION",
330 [BTF_KIND_ENUM] = "ENUM",
331 [BTF_KIND_FWD] = "FWD",
332 [BTF_KIND_TYPEDEF] = "TYPEDEF",
333 [BTF_KIND_VOLATILE] = "VOLATILE",
334 [BTF_KIND_CONST] = "CONST",
335 [BTF_KIND_RESTRICT] = "RESTRICT",
336 [BTF_KIND_FUNC] = "FUNC",
337 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
338 [BTF_KIND_VAR] = "VAR",
339 [BTF_KIND_DATASEC] = "DATASEC",
340 [BTF_KIND_FLOAT] = "FLOAT",
341 [BTF_KIND_DECL_TAG] = "DECL_TAG",
342 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
343 [BTF_KIND_ENUM64] = "ENUM64",
344};
345
346const char *btf_type_str(const struct btf_type *t)
347{
348 return btf_kind_str[BTF_INFO_KIND(t->info)];
349}
350
351/* Chunk size we use in safe copy of data to be shown. */
352#define BTF_SHOW_OBJ_SAFE_SIZE 32
353
354/*
355 * This is the maximum size of a base type value (equivalent to a
356 * 128-bit int); if we are at the end of our safe buffer and have
357 * less than 16 bytes space we can't be assured of being able
358 * to copy the next type safely, so in such cases we will initiate
359 * a new copy.
360 */
361#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
362
363/* Type name size */
364#define BTF_SHOW_NAME_SIZE 80
365
366/*
367 * The suffix of a type that indicates it cannot alias another type when
368 * comparing BTF IDs for kfunc invocations.
369 */
370#define NOCAST_ALIAS_SUFFIX "___init"
371
372/*
373 * Common data to all BTF show operations. Private show functions can add
374 * their own data to a structure containing a struct btf_show and consult it
375 * in the show callback. See btf_type_show() below.
376 *
377 * One challenge with showing nested data is we want to skip 0-valued
378 * data, but in order to figure out whether a nested object is all zeros
379 * we need to walk through it. As a result, we need to make two passes
380 * when handling structs, unions and arrays; the first path simply looks
381 * for nonzero data, while the second actually does the display. The first
382 * pass is signalled by show->state.depth_check being set, and if we
383 * encounter a non-zero value we set show->state.depth_to_show to
384 * the depth at which we encountered it. When we have completed the
385 * first pass, we will know if anything needs to be displayed if
386 * depth_to_show > depth. See btf_[struct,array]_show() for the
387 * implementation of this.
388 *
389 * Another problem is we want to ensure the data for display is safe to
390 * access. To support this, the anonymous "struct {} obj" tracks the data
391 * object and our safe copy of it. We copy portions of the data needed
392 * to the object "copy" buffer, but because its size is limited to
393 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
394 * traverse larger objects for display.
395 *
396 * The various data type show functions all start with a call to
397 * btf_show_start_type() which returns a pointer to the safe copy
398 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
399 * raw data itself). btf_show_obj_safe() is responsible for
400 * using copy_from_kernel_nofault() to update the safe data if necessary
401 * as we traverse the object's data. skbuff-like semantics are
402 * used:
403 *
404 * - obj.head points to the start of the toplevel object for display
405 * - obj.size is the size of the toplevel object
406 * - obj.data points to the current point in the original data at
407 * which our safe data starts. obj.data will advance as we copy
408 * portions of the data.
409 *
410 * In most cases a single copy will suffice, but larger data structures
411 * such as "struct task_struct" will require many copies. The logic in
412 * btf_show_obj_safe() handles the logic that determines if a new
413 * copy_from_kernel_nofault() is needed.
414 */
415struct btf_show {
416 u64 flags;
417 void *target; /* target of show operation (seq file, buffer) */
418 __printf(2, 0) void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
419 const struct btf *btf;
420 /* below are used during iteration */
421 struct {
422 u8 depth;
423 u8 depth_to_show;
424 u8 depth_check;
425 u8 array_member:1,
426 array_terminated:1;
427 u16 array_encoding;
428 u32 type_id;
429 int status; /* non-zero for error */
430 const struct btf_type *type;
431 const struct btf_member *member;
432 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
433 } state;
434 struct {
435 u32 size;
436 void *head;
437 void *data;
438 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
439 } obj;
440};
441
442struct btf_kind_operations {
443 s32 (*check_meta)(struct btf_verifier_env *env,
444 const struct btf_type *t,
445 u32 meta_left);
446 int (*resolve)(struct btf_verifier_env *env,
447 const struct resolve_vertex *v);
448 int (*check_member)(struct btf_verifier_env *env,
449 const struct btf_type *struct_type,
450 const struct btf_member *member,
451 const struct btf_type *member_type);
452 int (*check_kflag_member)(struct btf_verifier_env *env,
453 const struct btf_type *struct_type,
454 const struct btf_member *member,
455 const struct btf_type *member_type);
456 void (*log_details)(struct btf_verifier_env *env,
457 const struct btf_type *t);
458 void (*show)(const struct btf *btf, const struct btf_type *t,
459 u32 type_id, void *data, u8 bits_offsets,
460 struct btf_show *show);
461};
462
463static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
464static struct btf_type btf_void;
465
466static int btf_resolve(struct btf_verifier_env *env,
467 const struct btf_type *t, u32 type_id);
468
469static int btf_func_check(struct btf_verifier_env *env,
470 const struct btf_type *t);
471
472static bool btf_type_is_modifier(const struct btf_type *t)
473{
474 /* Some of them is not strictly a C modifier
475 * but they are grouped into the same bucket
476 * for BTF concern:
477 * A type (t) that refers to another
478 * type through t->type AND its size cannot
479 * be determined without following the t->type.
480 *
481 * ptr does not fall into this bucket
482 * because its size is always sizeof(void *).
483 */
484 switch (BTF_INFO_KIND(t->info)) {
485 case BTF_KIND_TYPEDEF:
486 case BTF_KIND_VOLATILE:
487 case BTF_KIND_CONST:
488 case BTF_KIND_RESTRICT:
489 case BTF_KIND_TYPE_TAG:
490 return true;
491 }
492
493 return false;
494}
495
496bool btf_type_is_void(const struct btf_type *t)
497{
498 return t == &btf_void;
499}
500
501static bool btf_type_is_datasec(const struct btf_type *t)
502{
503 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
504}
505
506static bool btf_type_is_decl_tag(const struct btf_type *t)
507{
508 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
509}
510
511static bool btf_type_nosize(const struct btf_type *t)
512{
513 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
514 btf_type_is_func(t) || btf_type_is_func_proto(t) ||
515 btf_type_is_decl_tag(t);
516}
517
518static bool btf_type_nosize_or_null(const struct btf_type *t)
519{
520 return !t || btf_type_nosize(t);
521}
522
523static bool btf_type_is_decl_tag_target(const struct btf_type *t)
524{
525 return btf_type_is_func(t) || btf_type_is_struct(t) ||
526 btf_type_is_var(t) || btf_type_is_typedef(t);
527}
528
529bool btf_is_vmlinux(const struct btf *btf)
530{
531 return btf->kernel_btf && !btf->base_btf;
532}
533
534u32 btf_nr_types(const struct btf *btf)
535{
536 u32 total = 0;
537
538 while (btf) {
539 total += btf->nr_types;
540 btf = btf->base_btf;
541 }
542
543 return total;
544}
545
546s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
547{
548 const struct btf_type *t;
549 const char *tname;
550 u32 i, total;
551
552 total = btf_nr_types(btf);
553 for (i = 1; i < total; i++) {
554 t = btf_type_by_id(btf, i);
555 if (BTF_INFO_KIND(t->info) != kind)
556 continue;
557
558 tname = btf_name_by_offset(btf, t->name_off);
559 if (!strcmp(tname, name))
560 return i;
561 }
562
563 return -ENOENT;
564}
565
566s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
567{
568 struct btf *btf;
569 s32 ret;
570 int id;
571
572 btf = bpf_get_btf_vmlinux();
573 if (IS_ERR(btf))
574 return PTR_ERR(btf);
575 if (!btf)
576 return -EINVAL;
577
578 ret = btf_find_by_name_kind(btf, name, kind);
579 /* ret is never zero, since btf_find_by_name_kind returns
580 * positive btf_id or negative error.
581 */
582 if (ret > 0) {
583 btf_get(btf);
584 *btf_p = btf;
585 return ret;
586 }
587
588 /* If name is not found in vmlinux's BTF then search in module's BTFs */
589 spin_lock_bh(&btf_idr_lock);
590 idr_for_each_entry(&btf_idr, btf, id) {
591 if (!btf_is_module(btf))
592 continue;
593 /* linear search could be slow hence unlock/lock
594 * the IDR to avoiding holding it for too long
595 */
596 btf_get(btf);
597 spin_unlock_bh(&btf_idr_lock);
598 ret = btf_find_by_name_kind(btf, name, kind);
599 if (ret > 0) {
600 *btf_p = btf;
601 return ret;
602 }
603 btf_put(btf);
604 spin_lock_bh(&btf_idr_lock);
605 }
606 spin_unlock_bh(&btf_idr_lock);
607 return ret;
608}
609
610const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
611 u32 id, u32 *res_id)
612{
613 const struct btf_type *t = btf_type_by_id(btf, id);
614
615 while (btf_type_is_modifier(t)) {
616 id = t->type;
617 t = btf_type_by_id(btf, t->type);
618 }
619
620 if (res_id)
621 *res_id = id;
622
623 return t;
624}
625
626const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
627 u32 id, u32 *res_id)
628{
629 const struct btf_type *t;
630
631 t = btf_type_skip_modifiers(btf, id, NULL);
632 if (!btf_type_is_ptr(t))
633 return NULL;
634
635 return btf_type_skip_modifiers(btf, t->type, res_id);
636}
637
638const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
639 u32 id, u32 *res_id)
640{
641 const struct btf_type *ptype;
642
643 ptype = btf_type_resolve_ptr(btf, id, res_id);
644 if (ptype && btf_type_is_func_proto(ptype))
645 return ptype;
646
647 return NULL;
648}
649
650/* Types that act only as a source, not sink or intermediate
651 * type when resolving.
652 */
653static bool btf_type_is_resolve_source_only(const struct btf_type *t)
654{
655 return btf_type_is_var(t) ||
656 btf_type_is_decl_tag(t) ||
657 btf_type_is_datasec(t);
658}
659
660/* What types need to be resolved?
661 *
662 * btf_type_is_modifier() is an obvious one.
663 *
664 * btf_type_is_struct() because its member refers to
665 * another type (through member->type).
666 *
667 * btf_type_is_var() because the variable refers to
668 * another type. btf_type_is_datasec() holds multiple
669 * btf_type_is_var() types that need resolving.
670 *
671 * btf_type_is_array() because its element (array->type)
672 * refers to another type. Array can be thought of a
673 * special case of struct while array just has the same
674 * member-type repeated by array->nelems of times.
675 */
676static bool btf_type_needs_resolve(const struct btf_type *t)
677{
678 return btf_type_is_modifier(t) ||
679 btf_type_is_ptr(t) ||
680 btf_type_is_struct(t) ||
681 btf_type_is_array(t) ||
682 btf_type_is_var(t) ||
683 btf_type_is_func(t) ||
684 btf_type_is_decl_tag(t) ||
685 btf_type_is_datasec(t);
686}
687
688/* t->size can be used */
689static bool btf_type_has_size(const struct btf_type *t)
690{
691 switch (BTF_INFO_KIND(t->info)) {
692 case BTF_KIND_INT:
693 case BTF_KIND_STRUCT:
694 case BTF_KIND_UNION:
695 case BTF_KIND_ENUM:
696 case BTF_KIND_DATASEC:
697 case BTF_KIND_FLOAT:
698 case BTF_KIND_ENUM64:
699 return true;
700 }
701
702 return false;
703}
704
705static const char *btf_int_encoding_str(u8 encoding)
706{
707 if (encoding == 0)
708 return "(none)";
709 else if (encoding == BTF_INT_SIGNED)
710 return "SIGNED";
711 else if (encoding == BTF_INT_CHAR)
712 return "CHAR";
713 else if (encoding == BTF_INT_BOOL)
714 return "BOOL";
715 else
716 return "UNKN";
717}
718
719static u32 btf_type_int(const struct btf_type *t)
720{
721 return *(u32 *)(t + 1);
722}
723
724static const struct btf_array *btf_type_array(const struct btf_type *t)
725{
726 return (const struct btf_array *)(t + 1);
727}
728
729static const struct btf_enum *btf_type_enum(const struct btf_type *t)
730{
731 return (const struct btf_enum *)(t + 1);
732}
733
734static const struct btf_var *btf_type_var(const struct btf_type *t)
735{
736 return (const struct btf_var *)(t + 1);
737}
738
739static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
740{
741 return (const struct btf_decl_tag *)(t + 1);
742}
743
744static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
745{
746 return (const struct btf_enum64 *)(t + 1);
747}
748
749static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
750{
751 return kind_ops[BTF_INFO_KIND(t->info)];
752}
753
754static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
755{
756 if (!BTF_STR_OFFSET_VALID(offset))
757 return false;
758
759 while (offset < btf->start_str_off)
760 btf = btf->base_btf;
761
762 offset -= btf->start_str_off;
763 return offset < btf->hdr.str_len;
764}
765
766static bool __btf_name_char_ok(char c, bool first)
767{
768 if ((first ? !isalpha(c) :
769 !isalnum(c)) &&
770 c != '_' &&
771 c != '.')
772 return false;
773 return true;
774}
775
776const char *btf_str_by_offset(const struct btf *btf, u32 offset)
777{
778 while (offset < btf->start_str_off)
779 btf = btf->base_btf;
780
781 offset -= btf->start_str_off;
782 if (offset < btf->hdr.str_len)
783 return &btf->strings[offset];
784
785 return NULL;
786}
787
788static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
789{
790 /* offset must be valid */
791 const char *src = btf_str_by_offset(btf, offset);
792 const char *src_limit;
793
794 if (!__btf_name_char_ok(*src, true))
795 return false;
796
797 /* set a limit on identifier length */
798 src_limit = src + KSYM_NAME_LEN;
799 src++;
800 while (*src && src < src_limit) {
801 if (!__btf_name_char_ok(*src, false))
802 return false;
803 src++;
804 }
805
806 return !*src;
807}
808
809/* Allow any printable character in DATASEC names */
810static bool btf_name_valid_section(const struct btf *btf, u32 offset)
811{
812 /* offset must be valid */
813 const char *src = btf_str_by_offset(btf, offset);
814 const char *src_limit;
815
816 if (!*src)
817 return false;
818
819 /* set a limit on identifier length */
820 src_limit = src + KSYM_NAME_LEN;
821 while (*src && src < src_limit) {
822 if (!isprint(*src))
823 return false;
824 src++;
825 }
826
827 return !*src;
828}
829
830static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
831{
832 const char *name;
833
834 if (!offset)
835 return "(anon)";
836
837 name = btf_str_by_offset(btf, offset);
838 return name ?: "(invalid-name-offset)";
839}
840
841const char *btf_name_by_offset(const struct btf *btf, u32 offset)
842{
843 return btf_str_by_offset(btf, offset);
844}
845
846const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
847{
848 while (type_id < btf->start_id)
849 btf = btf->base_btf;
850
851 type_id -= btf->start_id;
852 if (type_id >= btf->nr_types)
853 return NULL;
854 return btf->types[type_id];
855}
856EXPORT_SYMBOL_GPL(btf_type_by_id);
857
858/*
859 * Regular int is not a bit field and it must be either
860 * u8/u16/u32/u64 or __int128.
861 */
862static bool btf_type_int_is_regular(const struct btf_type *t)
863{
864 u8 nr_bits, nr_bytes;
865 u32 int_data;
866
867 int_data = btf_type_int(t);
868 nr_bits = BTF_INT_BITS(int_data);
869 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
870 if (BITS_PER_BYTE_MASKED(nr_bits) ||
871 BTF_INT_OFFSET(int_data) ||
872 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
873 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
874 nr_bytes != (2 * sizeof(u64)))) {
875 return false;
876 }
877
878 return true;
879}
880
881/*
882 * Check that given struct member is a regular int with expected
883 * offset and size.
884 */
885bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
886 const struct btf_member *m,
887 u32 expected_offset, u32 expected_size)
888{
889 const struct btf_type *t;
890 u32 id, int_data;
891 u8 nr_bits;
892
893 id = m->type;
894 t = btf_type_id_size(btf, &id, NULL);
895 if (!t || !btf_type_is_int(t))
896 return false;
897
898 int_data = btf_type_int(t);
899 nr_bits = BTF_INT_BITS(int_data);
900 if (btf_type_kflag(s)) {
901 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
902 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
903
904 /* if kflag set, int should be a regular int and
905 * bit offset should be at byte boundary.
906 */
907 return !bitfield_size &&
908 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
909 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
910 }
911
912 if (BTF_INT_OFFSET(int_data) ||
913 BITS_PER_BYTE_MASKED(m->offset) ||
914 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
915 BITS_PER_BYTE_MASKED(nr_bits) ||
916 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
917 return false;
918
919 return true;
920}
921
922/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
923static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
924 u32 id)
925{
926 const struct btf_type *t = btf_type_by_id(btf, id);
927
928 while (btf_type_is_modifier(t) &&
929 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
930 t = btf_type_by_id(btf, t->type);
931 }
932
933 return t;
934}
935
936#define BTF_SHOW_MAX_ITER 10
937
938#define BTF_KIND_BIT(kind) (1ULL << kind)
939
940/*
941 * Populate show->state.name with type name information.
942 * Format of type name is
943 *
944 * [.member_name = ] (type_name)
945 */
946static const char *btf_show_name(struct btf_show *show)
947{
948 /* BTF_MAX_ITER array suffixes "[]" */
949 const char *array_suffixes = "[][][][][][][][][][]";
950 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
951 /* BTF_MAX_ITER pointer suffixes "*" */
952 const char *ptr_suffixes = "**********";
953 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
954 const char *name = NULL, *prefix = "", *parens = "";
955 const struct btf_member *m = show->state.member;
956 const struct btf_type *t;
957 const struct btf_array *array;
958 u32 id = show->state.type_id;
959 const char *member = NULL;
960 bool show_member = false;
961 u64 kinds = 0;
962 int i;
963
964 show->state.name[0] = '\0';
965
966 /*
967 * Don't show type name if we're showing an array member;
968 * in that case we show the array type so don't need to repeat
969 * ourselves for each member.
970 */
971 if (show->state.array_member)
972 return "";
973
974 /* Retrieve member name, if any. */
975 if (m) {
976 member = btf_name_by_offset(show->btf, m->name_off);
977 show_member = strlen(member) > 0;
978 id = m->type;
979 }
980
981 /*
982 * Start with type_id, as we have resolved the struct btf_type *
983 * via btf_modifier_show() past the parent typedef to the child
984 * struct, int etc it is defined as. In such cases, the type_id
985 * still represents the starting type while the struct btf_type *
986 * in our show->state points at the resolved type of the typedef.
987 */
988 t = btf_type_by_id(show->btf, id);
989 if (!t)
990 return "";
991
992 /*
993 * The goal here is to build up the right number of pointer and
994 * array suffixes while ensuring the type name for a typedef
995 * is represented. Along the way we accumulate a list of
996 * BTF kinds we have encountered, since these will inform later
997 * display; for example, pointer types will not require an
998 * opening "{" for struct, we will just display the pointer value.
999 *
1000 * We also want to accumulate the right number of pointer or array
1001 * indices in the format string while iterating until we get to
1002 * the typedef/pointee/array member target type.
1003 *
1004 * We start by pointing at the end of pointer and array suffix
1005 * strings; as we accumulate pointers and arrays we move the pointer
1006 * or array string backwards so it will show the expected number of
1007 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
1008 * and/or arrays and typedefs are supported as a precaution.
1009 *
1010 * We also want to get typedef name while proceeding to resolve
1011 * type it points to so that we can add parentheses if it is a
1012 * "typedef struct" etc.
1013 */
1014 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
1015
1016 switch (BTF_INFO_KIND(t->info)) {
1017 case BTF_KIND_TYPEDEF:
1018 if (!name)
1019 name = btf_name_by_offset(show->btf,
1020 t->name_off);
1021 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1022 id = t->type;
1023 break;
1024 case BTF_KIND_ARRAY:
1025 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1026 parens = "[";
1027 if (!t)
1028 return "";
1029 array = btf_type_array(t);
1030 if (array_suffix > array_suffixes)
1031 array_suffix -= 2;
1032 id = array->type;
1033 break;
1034 case BTF_KIND_PTR:
1035 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1036 if (ptr_suffix > ptr_suffixes)
1037 ptr_suffix -= 1;
1038 id = t->type;
1039 break;
1040 default:
1041 id = 0;
1042 break;
1043 }
1044 if (!id)
1045 break;
1046 t = btf_type_skip_qualifiers(show->btf, id);
1047 }
1048 /* We may not be able to represent this type; bail to be safe */
1049 if (i == BTF_SHOW_MAX_ITER)
1050 return "";
1051
1052 if (!name)
1053 name = btf_name_by_offset(show->btf, t->name_off);
1054
1055 switch (BTF_INFO_KIND(t->info)) {
1056 case BTF_KIND_STRUCT:
1057 case BTF_KIND_UNION:
1058 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1059 "struct" : "union";
1060 /* if it's an array of struct/union, parens is already set */
1061 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1062 parens = "{";
1063 break;
1064 case BTF_KIND_ENUM:
1065 case BTF_KIND_ENUM64:
1066 prefix = "enum";
1067 break;
1068 default:
1069 break;
1070 }
1071
1072 /* pointer does not require parens */
1073 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1074 parens = "";
1075 /* typedef does not require struct/union/enum prefix */
1076 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1077 prefix = "";
1078
1079 if (!name)
1080 name = "";
1081
1082 /* Even if we don't want type name info, we want parentheses etc */
1083 if (show->flags & BTF_SHOW_NONAME)
1084 snprintf(show->state.name, sizeof(show->state.name), "%s",
1085 parens);
1086 else
1087 snprintf(show->state.name, sizeof(show->state.name),
1088 "%s%s%s(%s%s%s%s%s%s)%s",
1089 /* first 3 strings comprise ".member = " */
1090 show_member ? "." : "",
1091 show_member ? member : "",
1092 show_member ? " = " : "",
1093 /* ...next is our prefix (struct, enum, etc) */
1094 prefix,
1095 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1096 /* ...this is the type name itself */
1097 name,
1098 /* ...suffixed by the appropriate '*', '[]' suffixes */
1099 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1100 array_suffix, parens);
1101
1102 return show->state.name;
1103}
1104
1105static const char *__btf_show_indent(struct btf_show *show)
1106{
1107 const char *indents = " ";
1108 const char *indent = &indents[strlen(indents)];
1109
1110 if ((indent - show->state.depth) >= indents)
1111 return indent - show->state.depth;
1112 return indents;
1113}
1114
1115static const char *btf_show_indent(struct btf_show *show)
1116{
1117 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1118}
1119
1120static const char *btf_show_newline(struct btf_show *show)
1121{
1122 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1123}
1124
1125static const char *btf_show_delim(struct btf_show *show)
1126{
1127 if (show->state.depth == 0)
1128 return "";
1129
1130 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1131 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1132 return "|";
1133
1134 return ",";
1135}
1136
1137__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1138{
1139 va_list args;
1140
1141 if (!show->state.depth_check) {
1142 va_start(args, fmt);
1143 show->showfn(show, fmt, args);
1144 va_end(args);
1145 }
1146}
1147
1148/* Macros are used here as btf_show_type_value[s]() prepends and appends
1149 * format specifiers to the format specifier passed in; these do the work of
1150 * adding indentation, delimiters etc while the caller simply has to specify
1151 * the type value(s) in the format specifier + value(s).
1152 */
1153#define btf_show_type_value(show, fmt, value) \
1154 do { \
1155 if ((value) != (__typeof__(value))0 || \
1156 (show->flags & BTF_SHOW_ZERO) || \
1157 show->state.depth == 0) { \
1158 btf_show(show, "%s%s" fmt "%s%s", \
1159 btf_show_indent(show), \
1160 btf_show_name(show), \
1161 value, btf_show_delim(show), \
1162 btf_show_newline(show)); \
1163 if (show->state.depth > show->state.depth_to_show) \
1164 show->state.depth_to_show = show->state.depth; \
1165 } \
1166 } while (0)
1167
1168#define btf_show_type_values(show, fmt, ...) \
1169 do { \
1170 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1171 btf_show_name(show), \
1172 __VA_ARGS__, btf_show_delim(show), \
1173 btf_show_newline(show)); \
1174 if (show->state.depth > show->state.depth_to_show) \
1175 show->state.depth_to_show = show->state.depth; \
1176 } while (0)
1177
1178/* How much is left to copy to safe buffer after @data? */
1179static int btf_show_obj_size_left(struct btf_show *show, void *data)
1180{
1181 return show->obj.head + show->obj.size - data;
1182}
1183
1184/* Is object pointed to by @data of @size already copied to our safe buffer? */
1185static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1186{
1187 return data >= show->obj.data &&
1188 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1189}
1190
1191/*
1192 * If object pointed to by @data of @size falls within our safe buffer, return
1193 * the equivalent pointer to the same safe data. Assumes
1194 * copy_from_kernel_nofault() has already happened and our safe buffer is
1195 * populated.
1196 */
1197static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1198{
1199 if (btf_show_obj_is_safe(show, data, size))
1200 return show->obj.safe + (data - show->obj.data);
1201 return NULL;
1202}
1203
1204/*
1205 * Return a safe-to-access version of data pointed to by @data.
1206 * We do this by copying the relevant amount of information
1207 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1208 *
1209 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1210 * safe copy is needed.
1211 *
1212 * Otherwise we need to determine if we have the required amount
1213 * of data (determined by the @data pointer and the size of the
1214 * largest base type we can encounter (represented by
1215 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1216 * that we will be able to print some of the current object,
1217 * and if more is needed a copy will be triggered.
1218 * Some objects such as structs will not fit into the buffer;
1219 * in such cases additional copies when we iterate over their
1220 * members may be needed.
1221 *
1222 * btf_show_obj_safe() is used to return a safe buffer for
1223 * btf_show_start_type(); this ensures that as we recurse into
1224 * nested types we always have safe data for the given type.
1225 * This approach is somewhat wasteful; it's possible for example
1226 * that when iterating over a large union we'll end up copying the
1227 * same data repeatedly, but the goal is safety not performance.
1228 * We use stack data as opposed to per-CPU buffers because the
1229 * iteration over a type can take some time, and preemption handling
1230 * would greatly complicate use of the safe buffer.
1231 */
1232static void *btf_show_obj_safe(struct btf_show *show,
1233 const struct btf_type *t,
1234 void *data)
1235{
1236 const struct btf_type *rt;
1237 int size_left, size;
1238 void *safe = NULL;
1239
1240 if (show->flags & BTF_SHOW_UNSAFE)
1241 return data;
1242
1243 rt = btf_resolve_size(show->btf, t, &size);
1244 if (IS_ERR(rt)) {
1245 show->state.status = PTR_ERR(rt);
1246 return NULL;
1247 }
1248
1249 /*
1250 * Is this toplevel object? If so, set total object size and
1251 * initialize pointers. Otherwise check if we still fall within
1252 * our safe object data.
1253 */
1254 if (show->state.depth == 0) {
1255 show->obj.size = size;
1256 show->obj.head = data;
1257 } else {
1258 /*
1259 * If the size of the current object is > our remaining
1260 * safe buffer we _may_ need to do a new copy. However
1261 * consider the case of a nested struct; it's size pushes
1262 * us over the safe buffer limit, but showing any individual
1263 * struct members does not. In such cases, we don't need
1264 * to initiate a fresh copy yet; however we definitely need
1265 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1266 * in our buffer, regardless of the current object size.
1267 * The logic here is that as we resolve types we will
1268 * hit a base type at some point, and we need to be sure
1269 * the next chunk of data is safely available to display
1270 * that type info safely. We cannot rely on the size of
1271 * the current object here because it may be much larger
1272 * than our current buffer (e.g. task_struct is 8k).
1273 * All we want to do here is ensure that we can print the
1274 * next basic type, which we can if either
1275 * - the current type size is within the safe buffer; or
1276 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1277 * the safe buffer.
1278 */
1279 safe = __btf_show_obj_safe(show, data,
1280 min(size,
1281 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1282 }
1283
1284 /*
1285 * We need a new copy to our safe object, either because we haven't
1286 * yet copied and are initializing safe data, or because the data
1287 * we want falls outside the boundaries of the safe object.
1288 */
1289 if (!safe) {
1290 size_left = btf_show_obj_size_left(show, data);
1291 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1292 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1293 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1294 data, size_left);
1295 if (!show->state.status) {
1296 show->obj.data = data;
1297 safe = show->obj.safe;
1298 }
1299 }
1300
1301 return safe;
1302}
1303
1304/*
1305 * Set the type we are starting to show and return a safe data pointer
1306 * to be used for showing the associated data.
1307 */
1308static void *btf_show_start_type(struct btf_show *show,
1309 const struct btf_type *t,
1310 u32 type_id, void *data)
1311{
1312 show->state.type = t;
1313 show->state.type_id = type_id;
1314 show->state.name[0] = '\0';
1315
1316 return btf_show_obj_safe(show, t, data);
1317}
1318
1319static void btf_show_end_type(struct btf_show *show)
1320{
1321 show->state.type = NULL;
1322 show->state.type_id = 0;
1323 show->state.name[0] = '\0';
1324}
1325
1326static void *btf_show_start_aggr_type(struct btf_show *show,
1327 const struct btf_type *t,
1328 u32 type_id, void *data)
1329{
1330 void *safe_data = btf_show_start_type(show, t, type_id, data);
1331
1332 if (!safe_data)
1333 return safe_data;
1334
1335 btf_show(show, "%s%s%s", btf_show_indent(show),
1336 btf_show_name(show),
1337 btf_show_newline(show));
1338 show->state.depth++;
1339 return safe_data;
1340}
1341
1342static void btf_show_end_aggr_type(struct btf_show *show,
1343 const char *suffix)
1344{
1345 show->state.depth--;
1346 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1347 btf_show_delim(show), btf_show_newline(show));
1348 btf_show_end_type(show);
1349}
1350
1351static void btf_show_start_member(struct btf_show *show,
1352 const struct btf_member *m)
1353{
1354 show->state.member = m;
1355}
1356
1357static void btf_show_start_array_member(struct btf_show *show)
1358{
1359 show->state.array_member = 1;
1360 btf_show_start_member(show, NULL);
1361}
1362
1363static void btf_show_end_member(struct btf_show *show)
1364{
1365 show->state.member = NULL;
1366}
1367
1368static void btf_show_end_array_member(struct btf_show *show)
1369{
1370 show->state.array_member = 0;
1371 btf_show_end_member(show);
1372}
1373
1374static void *btf_show_start_array_type(struct btf_show *show,
1375 const struct btf_type *t,
1376 u32 type_id,
1377 u16 array_encoding,
1378 void *data)
1379{
1380 show->state.array_encoding = array_encoding;
1381 show->state.array_terminated = 0;
1382 return btf_show_start_aggr_type(show, t, type_id, data);
1383}
1384
1385static void btf_show_end_array_type(struct btf_show *show)
1386{
1387 show->state.array_encoding = 0;
1388 show->state.array_terminated = 0;
1389 btf_show_end_aggr_type(show, "]");
1390}
1391
1392static void *btf_show_start_struct_type(struct btf_show *show,
1393 const struct btf_type *t,
1394 u32 type_id,
1395 void *data)
1396{
1397 return btf_show_start_aggr_type(show, t, type_id, data);
1398}
1399
1400static void btf_show_end_struct_type(struct btf_show *show)
1401{
1402 btf_show_end_aggr_type(show, "}");
1403}
1404
1405__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1406 const char *fmt, ...)
1407{
1408 va_list args;
1409
1410 va_start(args, fmt);
1411 bpf_verifier_vlog(log, fmt, args);
1412 va_end(args);
1413}
1414
1415__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1416 const char *fmt, ...)
1417{
1418 struct bpf_verifier_log *log = &env->log;
1419 va_list args;
1420
1421 if (!bpf_verifier_log_needed(log))
1422 return;
1423
1424 va_start(args, fmt);
1425 bpf_verifier_vlog(log, fmt, args);
1426 va_end(args);
1427}
1428
1429__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1430 const struct btf_type *t,
1431 bool log_details,
1432 const char *fmt, ...)
1433{
1434 struct bpf_verifier_log *log = &env->log;
1435 struct btf *btf = env->btf;
1436 va_list args;
1437
1438 if (!bpf_verifier_log_needed(log))
1439 return;
1440
1441 if (log->level == BPF_LOG_KERNEL) {
1442 /* btf verifier prints all types it is processing via
1443 * btf_verifier_log_type(..., fmt = NULL).
1444 * Skip those prints for in-kernel BTF verification.
1445 */
1446 if (!fmt)
1447 return;
1448
1449 /* Skip logging when loading module BTF with mismatches permitted */
1450 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1451 return;
1452 }
1453
1454 __btf_verifier_log(log, "[%u] %s %s%s",
1455 env->log_type_id,
1456 btf_type_str(t),
1457 __btf_name_by_offset(btf, t->name_off),
1458 log_details ? " " : "");
1459
1460 if (log_details)
1461 btf_type_ops(t)->log_details(env, t);
1462
1463 if (fmt && *fmt) {
1464 __btf_verifier_log(log, " ");
1465 va_start(args, fmt);
1466 bpf_verifier_vlog(log, fmt, args);
1467 va_end(args);
1468 }
1469
1470 __btf_verifier_log(log, "\n");
1471}
1472
1473#define btf_verifier_log_type(env, t, ...) \
1474 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1475#define btf_verifier_log_basic(env, t, ...) \
1476 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1477
1478__printf(4, 5)
1479static void btf_verifier_log_member(struct btf_verifier_env *env,
1480 const struct btf_type *struct_type,
1481 const struct btf_member *member,
1482 const char *fmt, ...)
1483{
1484 struct bpf_verifier_log *log = &env->log;
1485 struct btf *btf = env->btf;
1486 va_list args;
1487
1488 if (!bpf_verifier_log_needed(log))
1489 return;
1490
1491 if (log->level == BPF_LOG_KERNEL) {
1492 if (!fmt)
1493 return;
1494
1495 /* Skip logging when loading module BTF with mismatches permitted */
1496 if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1497 return;
1498 }
1499
1500 /* The CHECK_META phase already did a btf dump.
1501 *
1502 * If member is logged again, it must hit an error in
1503 * parsing this member. It is useful to print out which
1504 * struct this member belongs to.
1505 */
1506 if (env->phase != CHECK_META)
1507 btf_verifier_log_type(env, struct_type, NULL);
1508
1509 if (btf_type_kflag(struct_type))
1510 __btf_verifier_log(log,
1511 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1512 __btf_name_by_offset(btf, member->name_off),
1513 member->type,
1514 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1515 BTF_MEMBER_BIT_OFFSET(member->offset));
1516 else
1517 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1518 __btf_name_by_offset(btf, member->name_off),
1519 member->type, member->offset);
1520
1521 if (fmt && *fmt) {
1522 __btf_verifier_log(log, " ");
1523 va_start(args, fmt);
1524 bpf_verifier_vlog(log, fmt, args);
1525 va_end(args);
1526 }
1527
1528 __btf_verifier_log(log, "\n");
1529}
1530
1531__printf(4, 5)
1532static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1533 const struct btf_type *datasec_type,
1534 const struct btf_var_secinfo *vsi,
1535 const char *fmt, ...)
1536{
1537 struct bpf_verifier_log *log = &env->log;
1538 va_list args;
1539
1540 if (!bpf_verifier_log_needed(log))
1541 return;
1542 if (log->level == BPF_LOG_KERNEL && !fmt)
1543 return;
1544 if (env->phase != CHECK_META)
1545 btf_verifier_log_type(env, datasec_type, NULL);
1546
1547 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1548 vsi->type, vsi->offset, vsi->size);
1549 if (fmt && *fmt) {
1550 __btf_verifier_log(log, " ");
1551 va_start(args, fmt);
1552 bpf_verifier_vlog(log, fmt, args);
1553 va_end(args);
1554 }
1555
1556 __btf_verifier_log(log, "\n");
1557}
1558
1559static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1560 u32 btf_data_size)
1561{
1562 struct bpf_verifier_log *log = &env->log;
1563 const struct btf *btf = env->btf;
1564 const struct btf_header *hdr;
1565
1566 if (!bpf_verifier_log_needed(log))
1567 return;
1568
1569 if (log->level == BPF_LOG_KERNEL)
1570 return;
1571 hdr = &btf->hdr;
1572 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1573 __btf_verifier_log(log, "version: %u\n", hdr->version);
1574 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1575 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1576 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1577 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1578 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1579 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1580 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1581}
1582
1583static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1584{
1585 struct btf *btf = env->btf;
1586
1587 if (btf->types_size == btf->nr_types) {
1588 /* Expand 'types' array */
1589
1590 struct btf_type **new_types;
1591 u32 expand_by, new_size;
1592
1593 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1594 btf_verifier_log(env, "Exceeded max num of types");
1595 return -E2BIG;
1596 }
1597
1598 expand_by = max_t(u32, btf->types_size >> 2, 16);
1599 new_size = min_t(u32, BTF_MAX_TYPE,
1600 btf->types_size + expand_by);
1601
1602 new_types = kvcalloc(new_size, sizeof(*new_types),
1603 GFP_KERNEL | __GFP_NOWARN);
1604 if (!new_types)
1605 return -ENOMEM;
1606
1607 if (btf->nr_types == 0) {
1608 if (!btf->base_btf) {
1609 /* lazily init VOID type */
1610 new_types[0] = &btf_void;
1611 btf->nr_types++;
1612 }
1613 } else {
1614 memcpy(new_types, btf->types,
1615 sizeof(*btf->types) * btf->nr_types);
1616 }
1617
1618 kvfree(btf->types);
1619 btf->types = new_types;
1620 btf->types_size = new_size;
1621 }
1622
1623 btf->types[btf->nr_types++] = t;
1624
1625 return 0;
1626}
1627
1628static int btf_alloc_id(struct btf *btf)
1629{
1630 int id;
1631
1632 idr_preload(GFP_KERNEL);
1633 spin_lock_bh(&btf_idr_lock);
1634 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1635 if (id > 0)
1636 btf->id = id;
1637 spin_unlock_bh(&btf_idr_lock);
1638 idr_preload_end();
1639
1640 if (WARN_ON_ONCE(!id))
1641 return -ENOSPC;
1642
1643 return id > 0 ? 0 : id;
1644}
1645
1646static void btf_free_id(struct btf *btf)
1647{
1648 unsigned long flags;
1649
1650 /*
1651 * In map-in-map, calling map_delete_elem() on outer
1652 * map will call bpf_map_put on the inner map.
1653 * It will then eventually call btf_free_id()
1654 * on the inner map. Some of the map_delete_elem()
1655 * implementation may have irq disabled, so
1656 * we need to use the _irqsave() version instead
1657 * of the _bh() version.
1658 */
1659 spin_lock_irqsave(&btf_idr_lock, flags);
1660 idr_remove(&btf_idr, btf->id);
1661 spin_unlock_irqrestore(&btf_idr_lock, flags);
1662}
1663
1664static void btf_free_kfunc_set_tab(struct btf *btf)
1665{
1666 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1667 int hook;
1668
1669 if (!tab)
1670 return;
1671 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1672 kfree(tab->sets[hook]);
1673 kfree(tab);
1674 btf->kfunc_set_tab = NULL;
1675}
1676
1677static void btf_free_dtor_kfunc_tab(struct btf *btf)
1678{
1679 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1680
1681 if (!tab)
1682 return;
1683 kfree(tab);
1684 btf->dtor_kfunc_tab = NULL;
1685}
1686
1687static void btf_struct_metas_free(struct btf_struct_metas *tab)
1688{
1689 int i;
1690
1691 if (!tab)
1692 return;
1693 for (i = 0; i < tab->cnt; i++)
1694 btf_record_free(tab->types[i].record);
1695 kfree(tab);
1696}
1697
1698static void btf_free_struct_meta_tab(struct btf *btf)
1699{
1700 struct btf_struct_metas *tab = btf->struct_meta_tab;
1701
1702 btf_struct_metas_free(tab);
1703 btf->struct_meta_tab = NULL;
1704}
1705
1706static void btf_free_struct_ops_tab(struct btf *btf)
1707{
1708 struct btf_struct_ops_tab *tab = btf->struct_ops_tab;
1709 u32 i;
1710
1711 if (!tab)
1712 return;
1713
1714 for (i = 0; i < tab->cnt; i++)
1715 bpf_struct_ops_desc_release(&tab->ops[i]);
1716
1717 kfree(tab);
1718 btf->struct_ops_tab = NULL;
1719}
1720
1721static void btf_free(struct btf *btf)
1722{
1723 btf_free_struct_meta_tab(btf);
1724 btf_free_dtor_kfunc_tab(btf);
1725 btf_free_kfunc_set_tab(btf);
1726 btf_free_struct_ops_tab(btf);
1727 kvfree(btf->types);
1728 kvfree(btf->resolved_sizes);
1729 kvfree(btf->resolved_ids);
1730 /* vmlinux does not allocate btf->data, it simply points it at
1731 * __start_BTF.
1732 */
1733 if (!btf_is_vmlinux(btf))
1734 kvfree(btf->data);
1735 kvfree(btf->base_id_map);
1736 kfree(btf);
1737}
1738
1739static void btf_free_rcu(struct rcu_head *rcu)
1740{
1741 struct btf *btf = container_of(rcu, struct btf, rcu);
1742
1743 btf_free(btf);
1744}
1745
1746const char *btf_get_name(const struct btf *btf)
1747{
1748 return btf->name;
1749}
1750
1751void btf_get(struct btf *btf)
1752{
1753 refcount_inc(&btf->refcnt);
1754}
1755
1756void btf_put(struct btf *btf)
1757{
1758 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1759 btf_free_id(btf);
1760 call_rcu(&btf->rcu, btf_free_rcu);
1761 }
1762}
1763
1764struct btf *btf_base_btf(const struct btf *btf)
1765{
1766 return btf->base_btf;
1767}
1768
1769const struct btf_header *btf_header(const struct btf *btf)
1770{
1771 return &btf->hdr;
1772}
1773
1774void btf_set_base_btf(struct btf *btf, const struct btf *base_btf)
1775{
1776 btf->base_btf = (struct btf *)base_btf;
1777 btf->start_id = btf_nr_types(base_btf);
1778 btf->start_str_off = base_btf->hdr.str_len;
1779}
1780
1781static int env_resolve_init(struct btf_verifier_env *env)
1782{
1783 struct btf *btf = env->btf;
1784 u32 nr_types = btf->nr_types;
1785 u32 *resolved_sizes = NULL;
1786 u32 *resolved_ids = NULL;
1787 u8 *visit_states = NULL;
1788
1789 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1790 GFP_KERNEL | __GFP_NOWARN);
1791 if (!resolved_sizes)
1792 goto nomem;
1793
1794 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1795 GFP_KERNEL | __GFP_NOWARN);
1796 if (!resolved_ids)
1797 goto nomem;
1798
1799 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1800 GFP_KERNEL | __GFP_NOWARN);
1801 if (!visit_states)
1802 goto nomem;
1803
1804 btf->resolved_sizes = resolved_sizes;
1805 btf->resolved_ids = resolved_ids;
1806 env->visit_states = visit_states;
1807
1808 return 0;
1809
1810nomem:
1811 kvfree(resolved_sizes);
1812 kvfree(resolved_ids);
1813 kvfree(visit_states);
1814 return -ENOMEM;
1815}
1816
1817static void btf_verifier_env_free(struct btf_verifier_env *env)
1818{
1819 kvfree(env->visit_states);
1820 kfree(env);
1821}
1822
1823static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1824 const struct btf_type *next_type)
1825{
1826 switch (env->resolve_mode) {
1827 case RESOLVE_TBD:
1828 /* int, enum or void is a sink */
1829 return !btf_type_needs_resolve(next_type);
1830 case RESOLVE_PTR:
1831 /* int, enum, void, struct, array, func or func_proto is a sink
1832 * for ptr
1833 */
1834 return !btf_type_is_modifier(next_type) &&
1835 !btf_type_is_ptr(next_type);
1836 case RESOLVE_STRUCT_OR_ARRAY:
1837 /* int, enum, void, ptr, func or func_proto is a sink
1838 * for struct and array
1839 */
1840 return !btf_type_is_modifier(next_type) &&
1841 !btf_type_is_array(next_type) &&
1842 !btf_type_is_struct(next_type);
1843 default:
1844 BUG();
1845 }
1846}
1847
1848static bool env_type_is_resolved(const struct btf_verifier_env *env,
1849 u32 type_id)
1850{
1851 /* base BTF types should be resolved by now */
1852 if (type_id < env->btf->start_id)
1853 return true;
1854
1855 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1856}
1857
1858static int env_stack_push(struct btf_verifier_env *env,
1859 const struct btf_type *t, u32 type_id)
1860{
1861 const struct btf *btf = env->btf;
1862 struct resolve_vertex *v;
1863
1864 if (env->top_stack == MAX_RESOLVE_DEPTH)
1865 return -E2BIG;
1866
1867 if (type_id < btf->start_id
1868 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1869 return -EEXIST;
1870
1871 env->visit_states[type_id - btf->start_id] = VISITED;
1872
1873 v = &env->stack[env->top_stack++];
1874 v->t = t;
1875 v->type_id = type_id;
1876 v->next_member = 0;
1877
1878 if (env->resolve_mode == RESOLVE_TBD) {
1879 if (btf_type_is_ptr(t))
1880 env->resolve_mode = RESOLVE_PTR;
1881 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1882 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1883 }
1884
1885 return 0;
1886}
1887
1888static void env_stack_set_next_member(struct btf_verifier_env *env,
1889 u16 next_member)
1890{
1891 env->stack[env->top_stack - 1].next_member = next_member;
1892}
1893
1894static void env_stack_pop_resolved(struct btf_verifier_env *env,
1895 u32 resolved_type_id,
1896 u32 resolved_size)
1897{
1898 u32 type_id = env->stack[--(env->top_stack)].type_id;
1899 struct btf *btf = env->btf;
1900
1901 type_id -= btf->start_id; /* adjust to local type id */
1902 btf->resolved_sizes[type_id] = resolved_size;
1903 btf->resolved_ids[type_id] = resolved_type_id;
1904 env->visit_states[type_id] = RESOLVED;
1905}
1906
1907static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1908{
1909 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1910}
1911
1912/* Resolve the size of a passed-in "type"
1913 *
1914 * type: is an array (e.g. u32 array[x][y])
1915 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1916 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1917 * corresponds to the return type.
1918 * *elem_type: u32
1919 * *elem_id: id of u32
1920 * *total_nelems: (x * y). Hence, individual elem size is
1921 * (*type_size / *total_nelems)
1922 * *type_id: id of type if it's changed within the function, 0 if not
1923 *
1924 * type: is not an array (e.g. const struct X)
1925 * return type: type "struct X"
1926 * *type_size: sizeof(struct X)
1927 * *elem_type: same as return type ("struct X")
1928 * *elem_id: 0
1929 * *total_nelems: 1
1930 * *type_id: id of type if it's changed within the function, 0 if not
1931 */
1932static const struct btf_type *
1933__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1934 u32 *type_size, const struct btf_type **elem_type,
1935 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1936{
1937 const struct btf_type *array_type = NULL;
1938 const struct btf_array *array = NULL;
1939 u32 i, size, nelems = 1, id = 0;
1940
1941 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1942 switch (BTF_INFO_KIND(type->info)) {
1943 /* type->size can be used */
1944 case BTF_KIND_INT:
1945 case BTF_KIND_STRUCT:
1946 case BTF_KIND_UNION:
1947 case BTF_KIND_ENUM:
1948 case BTF_KIND_FLOAT:
1949 case BTF_KIND_ENUM64:
1950 size = type->size;
1951 goto resolved;
1952
1953 case BTF_KIND_PTR:
1954 size = sizeof(void *);
1955 goto resolved;
1956
1957 /* Modifiers */
1958 case BTF_KIND_TYPEDEF:
1959 case BTF_KIND_VOLATILE:
1960 case BTF_KIND_CONST:
1961 case BTF_KIND_RESTRICT:
1962 case BTF_KIND_TYPE_TAG:
1963 id = type->type;
1964 type = btf_type_by_id(btf, type->type);
1965 break;
1966
1967 case BTF_KIND_ARRAY:
1968 if (!array_type)
1969 array_type = type;
1970 array = btf_type_array(type);
1971 if (nelems && array->nelems > U32_MAX / nelems)
1972 return ERR_PTR(-EINVAL);
1973 nelems *= array->nelems;
1974 type = btf_type_by_id(btf, array->type);
1975 break;
1976
1977 /* type without size */
1978 default:
1979 return ERR_PTR(-EINVAL);
1980 }
1981 }
1982
1983 return ERR_PTR(-EINVAL);
1984
1985resolved:
1986 if (nelems && size > U32_MAX / nelems)
1987 return ERR_PTR(-EINVAL);
1988
1989 *type_size = nelems * size;
1990 if (total_nelems)
1991 *total_nelems = nelems;
1992 if (elem_type)
1993 *elem_type = type;
1994 if (elem_id)
1995 *elem_id = array ? array->type : 0;
1996 if (type_id && id)
1997 *type_id = id;
1998
1999 return array_type ? : type;
2000}
2001
2002const struct btf_type *
2003btf_resolve_size(const struct btf *btf, const struct btf_type *type,
2004 u32 *type_size)
2005{
2006 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
2007}
2008
2009static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
2010{
2011 while (type_id < btf->start_id)
2012 btf = btf->base_btf;
2013
2014 return btf->resolved_ids[type_id - btf->start_id];
2015}
2016
2017/* The input param "type_id" must point to a needs_resolve type */
2018static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
2019 u32 *type_id)
2020{
2021 *type_id = btf_resolved_type_id(btf, *type_id);
2022 return btf_type_by_id(btf, *type_id);
2023}
2024
2025static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
2026{
2027 while (type_id < btf->start_id)
2028 btf = btf->base_btf;
2029
2030 return btf->resolved_sizes[type_id - btf->start_id];
2031}
2032
2033const struct btf_type *btf_type_id_size(const struct btf *btf,
2034 u32 *type_id, u32 *ret_size)
2035{
2036 const struct btf_type *size_type;
2037 u32 size_type_id = *type_id;
2038 u32 size = 0;
2039
2040 size_type = btf_type_by_id(btf, size_type_id);
2041 if (btf_type_nosize_or_null(size_type))
2042 return NULL;
2043
2044 if (btf_type_has_size(size_type)) {
2045 size = size_type->size;
2046 } else if (btf_type_is_array(size_type)) {
2047 size = btf_resolved_type_size(btf, size_type_id);
2048 } else if (btf_type_is_ptr(size_type)) {
2049 size = sizeof(void *);
2050 } else {
2051 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
2052 !btf_type_is_var(size_type)))
2053 return NULL;
2054
2055 size_type_id = btf_resolved_type_id(btf, size_type_id);
2056 size_type = btf_type_by_id(btf, size_type_id);
2057 if (btf_type_nosize_or_null(size_type))
2058 return NULL;
2059 else if (btf_type_has_size(size_type))
2060 size = size_type->size;
2061 else if (btf_type_is_array(size_type))
2062 size = btf_resolved_type_size(btf, size_type_id);
2063 else if (btf_type_is_ptr(size_type))
2064 size = sizeof(void *);
2065 else
2066 return NULL;
2067 }
2068
2069 *type_id = size_type_id;
2070 if (ret_size)
2071 *ret_size = size;
2072
2073 return size_type;
2074}
2075
2076static int btf_df_check_member(struct btf_verifier_env *env,
2077 const struct btf_type *struct_type,
2078 const struct btf_member *member,
2079 const struct btf_type *member_type)
2080{
2081 btf_verifier_log_basic(env, struct_type,
2082 "Unsupported check_member");
2083 return -EINVAL;
2084}
2085
2086static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2087 const struct btf_type *struct_type,
2088 const struct btf_member *member,
2089 const struct btf_type *member_type)
2090{
2091 btf_verifier_log_basic(env, struct_type,
2092 "Unsupported check_kflag_member");
2093 return -EINVAL;
2094}
2095
2096/* Used for ptr, array struct/union and float type members.
2097 * int, enum and modifier types have their specific callback functions.
2098 */
2099static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2100 const struct btf_type *struct_type,
2101 const struct btf_member *member,
2102 const struct btf_type *member_type)
2103{
2104 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2105 btf_verifier_log_member(env, struct_type, member,
2106 "Invalid member bitfield_size");
2107 return -EINVAL;
2108 }
2109
2110 /* bitfield size is 0, so member->offset represents bit offset only.
2111 * It is safe to call non kflag check_member variants.
2112 */
2113 return btf_type_ops(member_type)->check_member(env, struct_type,
2114 member,
2115 member_type);
2116}
2117
2118static int btf_df_resolve(struct btf_verifier_env *env,
2119 const struct resolve_vertex *v)
2120{
2121 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2122 return -EINVAL;
2123}
2124
2125static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2126 u32 type_id, void *data, u8 bits_offsets,
2127 struct btf_show *show)
2128{
2129 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2130}
2131
2132static int btf_int_check_member(struct btf_verifier_env *env,
2133 const struct btf_type *struct_type,
2134 const struct btf_member *member,
2135 const struct btf_type *member_type)
2136{
2137 u32 int_data = btf_type_int(member_type);
2138 u32 struct_bits_off = member->offset;
2139 u32 struct_size = struct_type->size;
2140 u32 nr_copy_bits;
2141 u32 bytes_offset;
2142
2143 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2144 btf_verifier_log_member(env, struct_type, member,
2145 "bits_offset exceeds U32_MAX");
2146 return -EINVAL;
2147 }
2148
2149 struct_bits_off += BTF_INT_OFFSET(int_data);
2150 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2151 nr_copy_bits = BTF_INT_BITS(int_data) +
2152 BITS_PER_BYTE_MASKED(struct_bits_off);
2153
2154 if (nr_copy_bits > BITS_PER_U128) {
2155 btf_verifier_log_member(env, struct_type, member,
2156 "nr_copy_bits exceeds 128");
2157 return -EINVAL;
2158 }
2159
2160 if (struct_size < bytes_offset ||
2161 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2162 btf_verifier_log_member(env, struct_type, member,
2163 "Member exceeds struct_size");
2164 return -EINVAL;
2165 }
2166
2167 return 0;
2168}
2169
2170static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2171 const struct btf_type *struct_type,
2172 const struct btf_member *member,
2173 const struct btf_type *member_type)
2174{
2175 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2176 u32 int_data = btf_type_int(member_type);
2177 u32 struct_size = struct_type->size;
2178 u32 nr_copy_bits;
2179
2180 /* a regular int type is required for the kflag int member */
2181 if (!btf_type_int_is_regular(member_type)) {
2182 btf_verifier_log_member(env, struct_type, member,
2183 "Invalid member base type");
2184 return -EINVAL;
2185 }
2186
2187 /* check sanity of bitfield size */
2188 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2189 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2190 nr_int_data_bits = BTF_INT_BITS(int_data);
2191 if (!nr_bits) {
2192 /* Not a bitfield member, member offset must be at byte
2193 * boundary.
2194 */
2195 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2196 btf_verifier_log_member(env, struct_type, member,
2197 "Invalid member offset");
2198 return -EINVAL;
2199 }
2200
2201 nr_bits = nr_int_data_bits;
2202 } else if (nr_bits > nr_int_data_bits) {
2203 btf_verifier_log_member(env, struct_type, member,
2204 "Invalid member bitfield_size");
2205 return -EINVAL;
2206 }
2207
2208 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2209 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2210 if (nr_copy_bits > BITS_PER_U128) {
2211 btf_verifier_log_member(env, struct_type, member,
2212 "nr_copy_bits exceeds 128");
2213 return -EINVAL;
2214 }
2215
2216 if (struct_size < bytes_offset ||
2217 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2218 btf_verifier_log_member(env, struct_type, member,
2219 "Member exceeds struct_size");
2220 return -EINVAL;
2221 }
2222
2223 return 0;
2224}
2225
2226static s32 btf_int_check_meta(struct btf_verifier_env *env,
2227 const struct btf_type *t,
2228 u32 meta_left)
2229{
2230 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2231 u16 encoding;
2232
2233 if (meta_left < meta_needed) {
2234 btf_verifier_log_basic(env, t,
2235 "meta_left:%u meta_needed:%u",
2236 meta_left, meta_needed);
2237 return -EINVAL;
2238 }
2239
2240 if (btf_type_vlen(t)) {
2241 btf_verifier_log_type(env, t, "vlen != 0");
2242 return -EINVAL;
2243 }
2244
2245 if (btf_type_kflag(t)) {
2246 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2247 return -EINVAL;
2248 }
2249
2250 int_data = btf_type_int(t);
2251 if (int_data & ~BTF_INT_MASK) {
2252 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2253 int_data);
2254 return -EINVAL;
2255 }
2256
2257 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2258
2259 if (nr_bits > BITS_PER_U128) {
2260 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2261 BITS_PER_U128);
2262 return -EINVAL;
2263 }
2264
2265 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2266 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2267 return -EINVAL;
2268 }
2269
2270 /*
2271 * Only one of the encoding bits is allowed and it
2272 * should be sufficient for the pretty print purpose (i.e. decoding).
2273 * Multiple bits can be allowed later if it is found
2274 * to be insufficient.
2275 */
2276 encoding = BTF_INT_ENCODING(int_data);
2277 if (encoding &&
2278 encoding != BTF_INT_SIGNED &&
2279 encoding != BTF_INT_CHAR &&
2280 encoding != BTF_INT_BOOL) {
2281 btf_verifier_log_type(env, t, "Unsupported encoding");
2282 return -ENOTSUPP;
2283 }
2284
2285 btf_verifier_log_type(env, t, NULL);
2286
2287 return meta_needed;
2288}
2289
2290static void btf_int_log(struct btf_verifier_env *env,
2291 const struct btf_type *t)
2292{
2293 int int_data = btf_type_int(t);
2294
2295 btf_verifier_log(env,
2296 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2297 t->size, BTF_INT_OFFSET(int_data),
2298 BTF_INT_BITS(int_data),
2299 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2300}
2301
2302static void btf_int128_print(struct btf_show *show, void *data)
2303{
2304 /* data points to a __int128 number.
2305 * Suppose
2306 * int128_num = *(__int128 *)data;
2307 * The below formulas shows what upper_num and lower_num represents:
2308 * upper_num = int128_num >> 64;
2309 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2310 */
2311 u64 upper_num, lower_num;
2312
2313#ifdef __BIG_ENDIAN_BITFIELD
2314 upper_num = *(u64 *)data;
2315 lower_num = *(u64 *)(data + 8);
2316#else
2317 upper_num = *(u64 *)(data + 8);
2318 lower_num = *(u64 *)data;
2319#endif
2320 if (upper_num == 0)
2321 btf_show_type_value(show, "0x%llx", lower_num);
2322 else
2323 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2324 lower_num);
2325}
2326
2327static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2328 u16 right_shift_bits)
2329{
2330 u64 upper_num, lower_num;
2331
2332#ifdef __BIG_ENDIAN_BITFIELD
2333 upper_num = print_num[0];
2334 lower_num = print_num[1];
2335#else
2336 upper_num = print_num[1];
2337 lower_num = print_num[0];
2338#endif
2339
2340 /* shake out un-needed bits by shift/or operations */
2341 if (left_shift_bits >= 64) {
2342 upper_num = lower_num << (left_shift_bits - 64);
2343 lower_num = 0;
2344 } else {
2345 upper_num = (upper_num << left_shift_bits) |
2346 (lower_num >> (64 - left_shift_bits));
2347 lower_num = lower_num << left_shift_bits;
2348 }
2349
2350 if (right_shift_bits >= 64) {
2351 lower_num = upper_num >> (right_shift_bits - 64);
2352 upper_num = 0;
2353 } else {
2354 lower_num = (lower_num >> right_shift_bits) |
2355 (upper_num << (64 - right_shift_bits));
2356 upper_num = upper_num >> right_shift_bits;
2357 }
2358
2359#ifdef __BIG_ENDIAN_BITFIELD
2360 print_num[0] = upper_num;
2361 print_num[1] = lower_num;
2362#else
2363 print_num[0] = lower_num;
2364 print_num[1] = upper_num;
2365#endif
2366}
2367
2368static void btf_bitfield_show(void *data, u8 bits_offset,
2369 u8 nr_bits, struct btf_show *show)
2370{
2371 u16 left_shift_bits, right_shift_bits;
2372 u8 nr_copy_bytes;
2373 u8 nr_copy_bits;
2374 u64 print_num[2] = {};
2375
2376 nr_copy_bits = nr_bits + bits_offset;
2377 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2378
2379 memcpy(print_num, data, nr_copy_bytes);
2380
2381#ifdef __BIG_ENDIAN_BITFIELD
2382 left_shift_bits = bits_offset;
2383#else
2384 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2385#endif
2386 right_shift_bits = BITS_PER_U128 - nr_bits;
2387
2388 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2389 btf_int128_print(show, print_num);
2390}
2391
2392
2393static void btf_int_bits_show(const struct btf *btf,
2394 const struct btf_type *t,
2395 void *data, u8 bits_offset,
2396 struct btf_show *show)
2397{
2398 u32 int_data = btf_type_int(t);
2399 u8 nr_bits = BTF_INT_BITS(int_data);
2400 u8 total_bits_offset;
2401
2402 /*
2403 * bits_offset is at most 7.
2404 * BTF_INT_OFFSET() cannot exceed 128 bits.
2405 */
2406 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2407 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2408 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2409 btf_bitfield_show(data, bits_offset, nr_bits, show);
2410}
2411
2412static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2413 u32 type_id, void *data, u8 bits_offset,
2414 struct btf_show *show)
2415{
2416 u32 int_data = btf_type_int(t);
2417 u8 encoding = BTF_INT_ENCODING(int_data);
2418 bool sign = encoding & BTF_INT_SIGNED;
2419 u8 nr_bits = BTF_INT_BITS(int_data);
2420 void *safe_data;
2421
2422 safe_data = btf_show_start_type(show, t, type_id, data);
2423 if (!safe_data)
2424 return;
2425
2426 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2427 BITS_PER_BYTE_MASKED(nr_bits)) {
2428 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2429 goto out;
2430 }
2431
2432 switch (nr_bits) {
2433 case 128:
2434 btf_int128_print(show, safe_data);
2435 break;
2436 case 64:
2437 if (sign)
2438 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2439 else
2440 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2441 break;
2442 case 32:
2443 if (sign)
2444 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2445 else
2446 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2447 break;
2448 case 16:
2449 if (sign)
2450 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2451 else
2452 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2453 break;
2454 case 8:
2455 if (show->state.array_encoding == BTF_INT_CHAR) {
2456 /* check for null terminator */
2457 if (show->state.array_terminated)
2458 break;
2459 if (*(char *)data == '\0') {
2460 show->state.array_terminated = 1;
2461 break;
2462 }
2463 if (isprint(*(char *)data)) {
2464 btf_show_type_value(show, "'%c'",
2465 *(char *)safe_data);
2466 break;
2467 }
2468 }
2469 if (sign)
2470 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2471 else
2472 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2473 break;
2474 default:
2475 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2476 break;
2477 }
2478out:
2479 btf_show_end_type(show);
2480}
2481
2482static const struct btf_kind_operations int_ops = {
2483 .check_meta = btf_int_check_meta,
2484 .resolve = btf_df_resolve,
2485 .check_member = btf_int_check_member,
2486 .check_kflag_member = btf_int_check_kflag_member,
2487 .log_details = btf_int_log,
2488 .show = btf_int_show,
2489};
2490
2491static int btf_modifier_check_member(struct btf_verifier_env *env,
2492 const struct btf_type *struct_type,
2493 const struct btf_member *member,
2494 const struct btf_type *member_type)
2495{
2496 const struct btf_type *resolved_type;
2497 u32 resolved_type_id = member->type;
2498 struct btf_member resolved_member;
2499 struct btf *btf = env->btf;
2500
2501 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2502 if (!resolved_type) {
2503 btf_verifier_log_member(env, struct_type, member,
2504 "Invalid member");
2505 return -EINVAL;
2506 }
2507
2508 resolved_member = *member;
2509 resolved_member.type = resolved_type_id;
2510
2511 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2512 &resolved_member,
2513 resolved_type);
2514}
2515
2516static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2517 const struct btf_type *struct_type,
2518 const struct btf_member *member,
2519 const struct btf_type *member_type)
2520{
2521 const struct btf_type *resolved_type;
2522 u32 resolved_type_id = member->type;
2523 struct btf_member resolved_member;
2524 struct btf *btf = env->btf;
2525
2526 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2527 if (!resolved_type) {
2528 btf_verifier_log_member(env, struct_type, member,
2529 "Invalid member");
2530 return -EINVAL;
2531 }
2532
2533 resolved_member = *member;
2534 resolved_member.type = resolved_type_id;
2535
2536 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2537 &resolved_member,
2538 resolved_type);
2539}
2540
2541static int btf_ptr_check_member(struct btf_verifier_env *env,
2542 const struct btf_type *struct_type,
2543 const struct btf_member *member,
2544 const struct btf_type *member_type)
2545{
2546 u32 struct_size, struct_bits_off, bytes_offset;
2547
2548 struct_size = struct_type->size;
2549 struct_bits_off = member->offset;
2550 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2551
2552 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2553 btf_verifier_log_member(env, struct_type, member,
2554 "Member is not byte aligned");
2555 return -EINVAL;
2556 }
2557
2558 if (struct_size - bytes_offset < sizeof(void *)) {
2559 btf_verifier_log_member(env, struct_type, member,
2560 "Member exceeds struct_size");
2561 return -EINVAL;
2562 }
2563
2564 return 0;
2565}
2566
2567static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2568 const struct btf_type *t,
2569 u32 meta_left)
2570{
2571 const char *value;
2572
2573 if (btf_type_vlen(t)) {
2574 btf_verifier_log_type(env, t, "vlen != 0");
2575 return -EINVAL;
2576 }
2577
2578 if (btf_type_kflag(t)) {
2579 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2580 return -EINVAL;
2581 }
2582
2583 if (!BTF_TYPE_ID_VALID(t->type)) {
2584 btf_verifier_log_type(env, t, "Invalid type_id");
2585 return -EINVAL;
2586 }
2587
2588 /* typedef/type_tag type must have a valid name, and other ref types,
2589 * volatile, const, restrict, should have a null name.
2590 */
2591 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2592 if (!t->name_off ||
2593 !btf_name_valid_identifier(env->btf, t->name_off)) {
2594 btf_verifier_log_type(env, t, "Invalid name");
2595 return -EINVAL;
2596 }
2597 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2598 value = btf_name_by_offset(env->btf, t->name_off);
2599 if (!value || !value[0]) {
2600 btf_verifier_log_type(env, t, "Invalid name");
2601 return -EINVAL;
2602 }
2603 } else {
2604 if (t->name_off) {
2605 btf_verifier_log_type(env, t, "Invalid name");
2606 return -EINVAL;
2607 }
2608 }
2609
2610 btf_verifier_log_type(env, t, NULL);
2611
2612 return 0;
2613}
2614
2615static int btf_modifier_resolve(struct btf_verifier_env *env,
2616 const struct resolve_vertex *v)
2617{
2618 const struct btf_type *t = v->t;
2619 const struct btf_type *next_type;
2620 u32 next_type_id = t->type;
2621 struct btf *btf = env->btf;
2622
2623 next_type = btf_type_by_id(btf, next_type_id);
2624 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2625 btf_verifier_log_type(env, v->t, "Invalid type_id");
2626 return -EINVAL;
2627 }
2628
2629 if (!env_type_is_resolve_sink(env, next_type) &&
2630 !env_type_is_resolved(env, next_type_id))
2631 return env_stack_push(env, next_type, next_type_id);
2632
2633 /* Figure out the resolved next_type_id with size.
2634 * They will be stored in the current modifier's
2635 * resolved_ids and resolved_sizes such that it can
2636 * save us a few type-following when we use it later (e.g. in
2637 * pretty print).
2638 */
2639 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2640 if (env_type_is_resolved(env, next_type_id))
2641 next_type = btf_type_id_resolve(btf, &next_type_id);
2642
2643 /* "typedef void new_void", "const void"...etc */
2644 if (!btf_type_is_void(next_type) &&
2645 !btf_type_is_fwd(next_type) &&
2646 !btf_type_is_func_proto(next_type)) {
2647 btf_verifier_log_type(env, v->t, "Invalid type_id");
2648 return -EINVAL;
2649 }
2650 }
2651
2652 env_stack_pop_resolved(env, next_type_id, 0);
2653
2654 return 0;
2655}
2656
2657static int btf_var_resolve(struct btf_verifier_env *env,
2658 const struct resolve_vertex *v)
2659{
2660 const struct btf_type *next_type;
2661 const struct btf_type *t = v->t;
2662 u32 next_type_id = t->type;
2663 struct btf *btf = env->btf;
2664
2665 next_type = btf_type_by_id(btf, next_type_id);
2666 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2667 btf_verifier_log_type(env, v->t, "Invalid type_id");
2668 return -EINVAL;
2669 }
2670
2671 if (!env_type_is_resolve_sink(env, next_type) &&
2672 !env_type_is_resolved(env, next_type_id))
2673 return env_stack_push(env, next_type, next_type_id);
2674
2675 if (btf_type_is_modifier(next_type)) {
2676 const struct btf_type *resolved_type;
2677 u32 resolved_type_id;
2678
2679 resolved_type_id = next_type_id;
2680 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2681
2682 if (btf_type_is_ptr(resolved_type) &&
2683 !env_type_is_resolve_sink(env, resolved_type) &&
2684 !env_type_is_resolved(env, resolved_type_id))
2685 return env_stack_push(env, resolved_type,
2686 resolved_type_id);
2687 }
2688
2689 /* We must resolve to something concrete at this point, no
2690 * forward types or similar that would resolve to size of
2691 * zero is allowed.
2692 */
2693 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2694 btf_verifier_log_type(env, v->t, "Invalid type_id");
2695 return -EINVAL;
2696 }
2697
2698 env_stack_pop_resolved(env, next_type_id, 0);
2699
2700 return 0;
2701}
2702
2703static int btf_ptr_resolve(struct btf_verifier_env *env,
2704 const struct resolve_vertex *v)
2705{
2706 const struct btf_type *next_type;
2707 const struct btf_type *t = v->t;
2708 u32 next_type_id = t->type;
2709 struct btf *btf = env->btf;
2710
2711 next_type = btf_type_by_id(btf, next_type_id);
2712 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2713 btf_verifier_log_type(env, v->t, "Invalid type_id");
2714 return -EINVAL;
2715 }
2716
2717 if (!env_type_is_resolve_sink(env, next_type) &&
2718 !env_type_is_resolved(env, next_type_id))
2719 return env_stack_push(env, next_type, next_type_id);
2720
2721 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2722 * the modifier may have stopped resolving when it was resolved
2723 * to a ptr (last-resolved-ptr).
2724 *
2725 * We now need to continue from the last-resolved-ptr to
2726 * ensure the last-resolved-ptr will not referring back to
2727 * the current ptr (t).
2728 */
2729 if (btf_type_is_modifier(next_type)) {
2730 const struct btf_type *resolved_type;
2731 u32 resolved_type_id;
2732
2733 resolved_type_id = next_type_id;
2734 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2735
2736 if (btf_type_is_ptr(resolved_type) &&
2737 !env_type_is_resolve_sink(env, resolved_type) &&
2738 !env_type_is_resolved(env, resolved_type_id))
2739 return env_stack_push(env, resolved_type,
2740 resolved_type_id);
2741 }
2742
2743 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2744 if (env_type_is_resolved(env, next_type_id))
2745 next_type = btf_type_id_resolve(btf, &next_type_id);
2746
2747 if (!btf_type_is_void(next_type) &&
2748 !btf_type_is_fwd(next_type) &&
2749 !btf_type_is_func_proto(next_type)) {
2750 btf_verifier_log_type(env, v->t, "Invalid type_id");
2751 return -EINVAL;
2752 }
2753 }
2754
2755 env_stack_pop_resolved(env, next_type_id, 0);
2756
2757 return 0;
2758}
2759
2760static void btf_modifier_show(const struct btf *btf,
2761 const struct btf_type *t,
2762 u32 type_id, void *data,
2763 u8 bits_offset, struct btf_show *show)
2764{
2765 if (btf->resolved_ids)
2766 t = btf_type_id_resolve(btf, &type_id);
2767 else
2768 t = btf_type_skip_modifiers(btf, type_id, NULL);
2769
2770 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2771}
2772
2773static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2774 u32 type_id, void *data, u8 bits_offset,
2775 struct btf_show *show)
2776{
2777 t = btf_type_id_resolve(btf, &type_id);
2778
2779 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2780}
2781
2782static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2783 u32 type_id, void *data, u8 bits_offset,
2784 struct btf_show *show)
2785{
2786 void *safe_data;
2787
2788 safe_data = btf_show_start_type(show, t, type_id, data);
2789 if (!safe_data)
2790 return;
2791
2792 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2793 if (show->flags & BTF_SHOW_PTR_RAW)
2794 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2795 else
2796 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2797 btf_show_end_type(show);
2798}
2799
2800static void btf_ref_type_log(struct btf_verifier_env *env,
2801 const struct btf_type *t)
2802{
2803 btf_verifier_log(env, "type_id=%u", t->type);
2804}
2805
2806static const struct btf_kind_operations modifier_ops = {
2807 .check_meta = btf_ref_type_check_meta,
2808 .resolve = btf_modifier_resolve,
2809 .check_member = btf_modifier_check_member,
2810 .check_kflag_member = btf_modifier_check_kflag_member,
2811 .log_details = btf_ref_type_log,
2812 .show = btf_modifier_show,
2813};
2814
2815static const struct btf_kind_operations ptr_ops = {
2816 .check_meta = btf_ref_type_check_meta,
2817 .resolve = btf_ptr_resolve,
2818 .check_member = btf_ptr_check_member,
2819 .check_kflag_member = btf_generic_check_kflag_member,
2820 .log_details = btf_ref_type_log,
2821 .show = btf_ptr_show,
2822};
2823
2824static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2825 const struct btf_type *t,
2826 u32 meta_left)
2827{
2828 if (btf_type_vlen(t)) {
2829 btf_verifier_log_type(env, t, "vlen != 0");
2830 return -EINVAL;
2831 }
2832
2833 if (t->type) {
2834 btf_verifier_log_type(env, t, "type != 0");
2835 return -EINVAL;
2836 }
2837
2838 /* fwd type must have a valid name */
2839 if (!t->name_off ||
2840 !btf_name_valid_identifier(env->btf, t->name_off)) {
2841 btf_verifier_log_type(env, t, "Invalid name");
2842 return -EINVAL;
2843 }
2844
2845 btf_verifier_log_type(env, t, NULL);
2846
2847 return 0;
2848}
2849
2850static void btf_fwd_type_log(struct btf_verifier_env *env,
2851 const struct btf_type *t)
2852{
2853 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2854}
2855
2856static const struct btf_kind_operations fwd_ops = {
2857 .check_meta = btf_fwd_check_meta,
2858 .resolve = btf_df_resolve,
2859 .check_member = btf_df_check_member,
2860 .check_kflag_member = btf_df_check_kflag_member,
2861 .log_details = btf_fwd_type_log,
2862 .show = btf_df_show,
2863};
2864
2865static int btf_array_check_member(struct btf_verifier_env *env,
2866 const struct btf_type *struct_type,
2867 const struct btf_member *member,
2868 const struct btf_type *member_type)
2869{
2870 u32 struct_bits_off = member->offset;
2871 u32 struct_size, bytes_offset;
2872 u32 array_type_id, array_size;
2873 struct btf *btf = env->btf;
2874
2875 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2876 btf_verifier_log_member(env, struct_type, member,
2877 "Member is not byte aligned");
2878 return -EINVAL;
2879 }
2880
2881 array_type_id = member->type;
2882 btf_type_id_size(btf, &array_type_id, &array_size);
2883 struct_size = struct_type->size;
2884 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2885 if (struct_size - bytes_offset < array_size) {
2886 btf_verifier_log_member(env, struct_type, member,
2887 "Member exceeds struct_size");
2888 return -EINVAL;
2889 }
2890
2891 return 0;
2892}
2893
2894static s32 btf_array_check_meta(struct btf_verifier_env *env,
2895 const struct btf_type *t,
2896 u32 meta_left)
2897{
2898 const struct btf_array *array = btf_type_array(t);
2899 u32 meta_needed = sizeof(*array);
2900
2901 if (meta_left < meta_needed) {
2902 btf_verifier_log_basic(env, t,
2903 "meta_left:%u meta_needed:%u",
2904 meta_left, meta_needed);
2905 return -EINVAL;
2906 }
2907
2908 /* array type should not have a name */
2909 if (t->name_off) {
2910 btf_verifier_log_type(env, t, "Invalid name");
2911 return -EINVAL;
2912 }
2913
2914 if (btf_type_vlen(t)) {
2915 btf_verifier_log_type(env, t, "vlen != 0");
2916 return -EINVAL;
2917 }
2918
2919 if (btf_type_kflag(t)) {
2920 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2921 return -EINVAL;
2922 }
2923
2924 if (t->size) {
2925 btf_verifier_log_type(env, t, "size != 0");
2926 return -EINVAL;
2927 }
2928
2929 /* Array elem type and index type cannot be in type void,
2930 * so !array->type and !array->index_type are not allowed.
2931 */
2932 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2933 btf_verifier_log_type(env, t, "Invalid elem");
2934 return -EINVAL;
2935 }
2936
2937 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2938 btf_verifier_log_type(env, t, "Invalid index");
2939 return -EINVAL;
2940 }
2941
2942 btf_verifier_log_type(env, t, NULL);
2943
2944 return meta_needed;
2945}
2946
2947static int btf_array_resolve(struct btf_verifier_env *env,
2948 const struct resolve_vertex *v)
2949{
2950 const struct btf_array *array = btf_type_array(v->t);
2951 const struct btf_type *elem_type, *index_type;
2952 u32 elem_type_id, index_type_id;
2953 struct btf *btf = env->btf;
2954 u32 elem_size;
2955
2956 /* Check array->index_type */
2957 index_type_id = array->index_type;
2958 index_type = btf_type_by_id(btf, index_type_id);
2959 if (btf_type_nosize_or_null(index_type) ||
2960 btf_type_is_resolve_source_only(index_type)) {
2961 btf_verifier_log_type(env, v->t, "Invalid index");
2962 return -EINVAL;
2963 }
2964
2965 if (!env_type_is_resolve_sink(env, index_type) &&
2966 !env_type_is_resolved(env, index_type_id))
2967 return env_stack_push(env, index_type, index_type_id);
2968
2969 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2970 if (!index_type || !btf_type_is_int(index_type) ||
2971 !btf_type_int_is_regular(index_type)) {
2972 btf_verifier_log_type(env, v->t, "Invalid index");
2973 return -EINVAL;
2974 }
2975
2976 /* Check array->type */
2977 elem_type_id = array->type;
2978 elem_type = btf_type_by_id(btf, elem_type_id);
2979 if (btf_type_nosize_or_null(elem_type) ||
2980 btf_type_is_resolve_source_only(elem_type)) {
2981 btf_verifier_log_type(env, v->t,
2982 "Invalid elem");
2983 return -EINVAL;
2984 }
2985
2986 if (!env_type_is_resolve_sink(env, elem_type) &&
2987 !env_type_is_resolved(env, elem_type_id))
2988 return env_stack_push(env, elem_type, elem_type_id);
2989
2990 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2991 if (!elem_type) {
2992 btf_verifier_log_type(env, v->t, "Invalid elem");
2993 return -EINVAL;
2994 }
2995
2996 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2997 btf_verifier_log_type(env, v->t, "Invalid array of int");
2998 return -EINVAL;
2999 }
3000
3001 if (array->nelems && elem_size > U32_MAX / array->nelems) {
3002 btf_verifier_log_type(env, v->t,
3003 "Array size overflows U32_MAX");
3004 return -EINVAL;
3005 }
3006
3007 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
3008
3009 return 0;
3010}
3011
3012static void btf_array_log(struct btf_verifier_env *env,
3013 const struct btf_type *t)
3014{
3015 const struct btf_array *array = btf_type_array(t);
3016
3017 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
3018 array->type, array->index_type, array->nelems);
3019}
3020
3021static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
3022 u32 type_id, void *data, u8 bits_offset,
3023 struct btf_show *show)
3024{
3025 const struct btf_array *array = btf_type_array(t);
3026 const struct btf_kind_operations *elem_ops;
3027 const struct btf_type *elem_type;
3028 u32 i, elem_size = 0, elem_type_id;
3029 u16 encoding = 0;
3030
3031 elem_type_id = array->type;
3032 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
3033 if (elem_type && btf_type_has_size(elem_type))
3034 elem_size = elem_type->size;
3035
3036 if (elem_type && btf_type_is_int(elem_type)) {
3037 u32 int_type = btf_type_int(elem_type);
3038
3039 encoding = BTF_INT_ENCODING(int_type);
3040
3041 /*
3042 * BTF_INT_CHAR encoding never seems to be set for
3043 * char arrays, so if size is 1 and element is
3044 * printable as a char, we'll do that.
3045 */
3046 if (elem_size == 1)
3047 encoding = BTF_INT_CHAR;
3048 }
3049
3050 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
3051 return;
3052
3053 if (!elem_type)
3054 goto out;
3055 elem_ops = btf_type_ops(elem_type);
3056
3057 for (i = 0; i < array->nelems; i++) {
3058
3059 btf_show_start_array_member(show);
3060
3061 elem_ops->show(btf, elem_type, elem_type_id, data,
3062 bits_offset, show);
3063 data += elem_size;
3064
3065 btf_show_end_array_member(show);
3066
3067 if (show->state.array_terminated)
3068 break;
3069 }
3070out:
3071 btf_show_end_array_type(show);
3072}
3073
3074static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3075 u32 type_id, void *data, u8 bits_offset,
3076 struct btf_show *show)
3077{
3078 const struct btf_member *m = show->state.member;
3079
3080 /*
3081 * First check if any members would be shown (are non-zero).
3082 * See comments above "struct btf_show" definition for more
3083 * details on how this works at a high-level.
3084 */
3085 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3086 if (!show->state.depth_check) {
3087 show->state.depth_check = show->state.depth + 1;
3088 show->state.depth_to_show = 0;
3089 }
3090 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3091 show->state.member = m;
3092
3093 if (show->state.depth_check != show->state.depth + 1)
3094 return;
3095 show->state.depth_check = 0;
3096
3097 if (show->state.depth_to_show <= show->state.depth)
3098 return;
3099 /*
3100 * Reaching here indicates we have recursed and found
3101 * non-zero array member(s).
3102 */
3103 }
3104 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3105}
3106
3107static const struct btf_kind_operations array_ops = {
3108 .check_meta = btf_array_check_meta,
3109 .resolve = btf_array_resolve,
3110 .check_member = btf_array_check_member,
3111 .check_kflag_member = btf_generic_check_kflag_member,
3112 .log_details = btf_array_log,
3113 .show = btf_array_show,
3114};
3115
3116static int btf_struct_check_member(struct btf_verifier_env *env,
3117 const struct btf_type *struct_type,
3118 const struct btf_member *member,
3119 const struct btf_type *member_type)
3120{
3121 u32 struct_bits_off = member->offset;
3122 u32 struct_size, bytes_offset;
3123
3124 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3125 btf_verifier_log_member(env, struct_type, member,
3126 "Member is not byte aligned");
3127 return -EINVAL;
3128 }
3129
3130 struct_size = struct_type->size;
3131 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3132 if (struct_size - bytes_offset < member_type->size) {
3133 btf_verifier_log_member(env, struct_type, member,
3134 "Member exceeds struct_size");
3135 return -EINVAL;
3136 }
3137
3138 return 0;
3139}
3140
3141static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3142 const struct btf_type *t,
3143 u32 meta_left)
3144{
3145 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3146 const struct btf_member *member;
3147 u32 meta_needed, last_offset;
3148 struct btf *btf = env->btf;
3149 u32 struct_size = t->size;
3150 u32 offset;
3151 u16 i;
3152
3153 meta_needed = btf_type_vlen(t) * sizeof(*member);
3154 if (meta_left < meta_needed) {
3155 btf_verifier_log_basic(env, t,
3156 "meta_left:%u meta_needed:%u",
3157 meta_left, meta_needed);
3158 return -EINVAL;
3159 }
3160
3161 /* struct type either no name or a valid one */
3162 if (t->name_off &&
3163 !btf_name_valid_identifier(env->btf, t->name_off)) {
3164 btf_verifier_log_type(env, t, "Invalid name");
3165 return -EINVAL;
3166 }
3167
3168 btf_verifier_log_type(env, t, NULL);
3169
3170 last_offset = 0;
3171 for_each_member(i, t, member) {
3172 if (!btf_name_offset_valid(btf, member->name_off)) {
3173 btf_verifier_log_member(env, t, member,
3174 "Invalid member name_offset:%u",
3175 member->name_off);
3176 return -EINVAL;
3177 }
3178
3179 /* struct member either no name or a valid one */
3180 if (member->name_off &&
3181 !btf_name_valid_identifier(btf, member->name_off)) {
3182 btf_verifier_log_member(env, t, member, "Invalid name");
3183 return -EINVAL;
3184 }
3185 /* A member cannot be in type void */
3186 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3187 btf_verifier_log_member(env, t, member,
3188 "Invalid type_id");
3189 return -EINVAL;
3190 }
3191
3192 offset = __btf_member_bit_offset(t, member);
3193 if (is_union && offset) {
3194 btf_verifier_log_member(env, t, member,
3195 "Invalid member bits_offset");
3196 return -EINVAL;
3197 }
3198
3199 /*
3200 * ">" instead of ">=" because the last member could be
3201 * "char a[0];"
3202 */
3203 if (last_offset > offset) {
3204 btf_verifier_log_member(env, t, member,
3205 "Invalid member bits_offset");
3206 return -EINVAL;
3207 }
3208
3209 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3210 btf_verifier_log_member(env, t, member,
3211 "Member bits_offset exceeds its struct size");
3212 return -EINVAL;
3213 }
3214
3215 btf_verifier_log_member(env, t, member, NULL);
3216 last_offset = offset;
3217 }
3218
3219 return meta_needed;
3220}
3221
3222static int btf_struct_resolve(struct btf_verifier_env *env,
3223 const struct resolve_vertex *v)
3224{
3225 const struct btf_member *member;
3226 int err;
3227 u16 i;
3228
3229 /* Before continue resolving the next_member,
3230 * ensure the last member is indeed resolved to a
3231 * type with size info.
3232 */
3233 if (v->next_member) {
3234 const struct btf_type *last_member_type;
3235 const struct btf_member *last_member;
3236 u32 last_member_type_id;
3237
3238 last_member = btf_type_member(v->t) + v->next_member - 1;
3239 last_member_type_id = last_member->type;
3240 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3241 last_member_type_id)))
3242 return -EINVAL;
3243
3244 last_member_type = btf_type_by_id(env->btf,
3245 last_member_type_id);
3246 if (btf_type_kflag(v->t))
3247 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3248 last_member,
3249 last_member_type);
3250 else
3251 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3252 last_member,
3253 last_member_type);
3254 if (err)
3255 return err;
3256 }
3257
3258 for_each_member_from(i, v->next_member, v->t, member) {
3259 u32 member_type_id = member->type;
3260 const struct btf_type *member_type = btf_type_by_id(env->btf,
3261 member_type_id);
3262
3263 if (btf_type_nosize_or_null(member_type) ||
3264 btf_type_is_resolve_source_only(member_type)) {
3265 btf_verifier_log_member(env, v->t, member,
3266 "Invalid member");
3267 return -EINVAL;
3268 }
3269
3270 if (!env_type_is_resolve_sink(env, member_type) &&
3271 !env_type_is_resolved(env, member_type_id)) {
3272 env_stack_set_next_member(env, i + 1);
3273 return env_stack_push(env, member_type, member_type_id);
3274 }
3275
3276 if (btf_type_kflag(v->t))
3277 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3278 member,
3279 member_type);
3280 else
3281 err = btf_type_ops(member_type)->check_member(env, v->t,
3282 member,
3283 member_type);
3284 if (err)
3285 return err;
3286 }
3287
3288 env_stack_pop_resolved(env, 0, 0);
3289
3290 return 0;
3291}
3292
3293static void btf_struct_log(struct btf_verifier_env *env,
3294 const struct btf_type *t)
3295{
3296 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3297}
3298
3299enum {
3300 BTF_FIELD_IGNORE = 0,
3301 BTF_FIELD_FOUND = 1,
3302};
3303
3304struct btf_field_info {
3305 enum btf_field_type type;
3306 u32 off;
3307 union {
3308 struct {
3309 u32 type_id;
3310 } kptr;
3311 struct {
3312 const char *node_name;
3313 u32 value_btf_id;
3314 } graph_root;
3315 };
3316};
3317
3318static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3319 u32 off, int sz, enum btf_field_type field_type,
3320 struct btf_field_info *info)
3321{
3322 if (!__btf_type_is_struct(t))
3323 return BTF_FIELD_IGNORE;
3324 if (t->size != sz)
3325 return BTF_FIELD_IGNORE;
3326 info->type = field_type;
3327 info->off = off;
3328 return BTF_FIELD_FOUND;
3329}
3330
3331static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3332 u32 off, int sz, struct btf_field_info *info, u32 field_mask)
3333{
3334 enum btf_field_type type;
3335 u32 res_id;
3336
3337 /* Permit modifiers on the pointer itself */
3338 if (btf_type_is_volatile(t))
3339 t = btf_type_by_id(btf, t->type);
3340 /* For PTR, sz is always == 8 */
3341 if (!btf_type_is_ptr(t))
3342 return BTF_FIELD_IGNORE;
3343 t = btf_type_by_id(btf, t->type);
3344
3345 if (!btf_type_is_type_tag(t))
3346 return BTF_FIELD_IGNORE;
3347 /* Reject extra tags */
3348 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3349 return -EINVAL;
3350 if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off)))
3351 type = BPF_KPTR_UNREF;
3352 else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3353 type = BPF_KPTR_REF;
3354 else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off)))
3355 type = BPF_KPTR_PERCPU;
3356 else if (!strcmp("uptr", __btf_name_by_offset(btf, t->name_off)))
3357 type = BPF_UPTR;
3358 else
3359 return -EINVAL;
3360
3361 if (!(type & field_mask))
3362 return BTF_FIELD_IGNORE;
3363
3364 /* Get the base type */
3365 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3366 /* Only pointer to struct is allowed */
3367 if (!__btf_type_is_struct(t))
3368 return -EINVAL;
3369
3370 info->type = type;
3371 info->off = off;
3372 info->kptr.type_id = res_id;
3373 return BTF_FIELD_FOUND;
3374}
3375
3376int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
3377 int comp_idx, const char *tag_key, int last_id)
3378{
3379 int len = strlen(tag_key);
3380 int i, n;
3381
3382 for (i = last_id + 1, n = btf_nr_types(btf); i < n; i++) {
3383 const struct btf_type *t = btf_type_by_id(btf, i);
3384
3385 if (!btf_type_is_decl_tag(t))
3386 continue;
3387 if (pt != btf_type_by_id(btf, t->type))
3388 continue;
3389 if (btf_type_decl_tag(t)->component_idx != comp_idx)
3390 continue;
3391 if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3392 continue;
3393 return i;
3394 }
3395 return -ENOENT;
3396}
3397
3398const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3399 int comp_idx, const char *tag_key)
3400{
3401 const char *value = NULL;
3402 const struct btf_type *t;
3403 int len, id;
3404
3405 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
3406 if (id < 0)
3407 return ERR_PTR(id);
3408
3409 t = btf_type_by_id(btf, id);
3410 len = strlen(tag_key);
3411 value = __btf_name_by_offset(btf, t->name_off) + len;
3412
3413 /* Prevent duplicate entries for same type */
3414 id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id);
3415 if (id >= 0)
3416 return ERR_PTR(-EEXIST);
3417
3418 return value;
3419}
3420
3421static int
3422btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3423 const struct btf_type *t, int comp_idx, u32 off,
3424 int sz, struct btf_field_info *info,
3425 enum btf_field_type head_type)
3426{
3427 const char *node_field_name;
3428 const char *value_type;
3429 s32 id;
3430
3431 if (!__btf_type_is_struct(t))
3432 return BTF_FIELD_IGNORE;
3433 if (t->size != sz)
3434 return BTF_FIELD_IGNORE;
3435 value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3436 if (IS_ERR(value_type))
3437 return -EINVAL;
3438 node_field_name = strstr(value_type, ":");
3439 if (!node_field_name)
3440 return -EINVAL;
3441 value_type = kstrndup(value_type, node_field_name - value_type, GFP_KERNEL | __GFP_NOWARN);
3442 if (!value_type)
3443 return -ENOMEM;
3444 id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3445 kfree(value_type);
3446 if (id < 0)
3447 return id;
3448 node_field_name++;
3449 if (str_is_empty(node_field_name))
3450 return -EINVAL;
3451 info->type = head_type;
3452 info->off = off;
3453 info->graph_root.value_btf_id = id;
3454 info->graph_root.node_name = node_field_name;
3455 return BTF_FIELD_FOUND;
3456}
3457
3458#define field_mask_test_name(field_type, field_type_str) \
3459 if (field_mask & field_type && !strcmp(name, field_type_str)) { \
3460 type = field_type; \
3461 goto end; \
3462 }
3463
3464static int btf_get_field_type(const struct btf *btf, const struct btf_type *var_type,
3465 u32 field_mask, u32 *seen_mask,
3466 int *align, int *sz)
3467{
3468 int type = 0;
3469 const char *name = __btf_name_by_offset(btf, var_type->name_off);
3470
3471 if (field_mask & BPF_SPIN_LOCK) {
3472 if (!strcmp(name, "bpf_spin_lock")) {
3473 if (*seen_mask & BPF_SPIN_LOCK)
3474 return -E2BIG;
3475 *seen_mask |= BPF_SPIN_LOCK;
3476 type = BPF_SPIN_LOCK;
3477 goto end;
3478 }
3479 }
3480 if (field_mask & BPF_TIMER) {
3481 if (!strcmp(name, "bpf_timer")) {
3482 if (*seen_mask & BPF_TIMER)
3483 return -E2BIG;
3484 *seen_mask |= BPF_TIMER;
3485 type = BPF_TIMER;
3486 goto end;
3487 }
3488 }
3489 if (field_mask & BPF_WORKQUEUE) {
3490 if (!strcmp(name, "bpf_wq")) {
3491 if (*seen_mask & BPF_WORKQUEUE)
3492 return -E2BIG;
3493 *seen_mask |= BPF_WORKQUEUE;
3494 type = BPF_WORKQUEUE;
3495 goto end;
3496 }
3497 }
3498 field_mask_test_name(BPF_LIST_HEAD, "bpf_list_head");
3499 field_mask_test_name(BPF_LIST_NODE, "bpf_list_node");
3500 field_mask_test_name(BPF_RB_ROOT, "bpf_rb_root");
3501 field_mask_test_name(BPF_RB_NODE, "bpf_rb_node");
3502 field_mask_test_name(BPF_REFCOUNT, "bpf_refcount");
3503
3504 /* Only return BPF_KPTR when all other types with matchable names fail */
3505 if (field_mask & (BPF_KPTR | BPF_UPTR) && !__btf_type_is_struct(var_type)) {
3506 type = BPF_KPTR_REF;
3507 goto end;
3508 }
3509 return 0;
3510end:
3511 *sz = btf_field_type_size(type);
3512 *align = btf_field_type_align(type);
3513 return type;
3514}
3515
3516#undef field_mask_test_name
3517
3518/* Repeat a number of fields for a specified number of times.
3519 *
3520 * Copy the fields starting from the first field and repeat them for
3521 * repeat_cnt times. The fields are repeated by adding the offset of each
3522 * field with
3523 * (i + 1) * elem_size
3524 * where i is the repeat index and elem_size is the size of an element.
3525 */
3526static int btf_repeat_fields(struct btf_field_info *info, int info_cnt,
3527 u32 field_cnt, u32 repeat_cnt, u32 elem_size)
3528{
3529 u32 i, j;
3530 u32 cur;
3531
3532 /* Ensure not repeating fields that should not be repeated. */
3533 for (i = 0; i < field_cnt; i++) {
3534 switch (info[i].type) {
3535 case BPF_KPTR_UNREF:
3536 case BPF_KPTR_REF:
3537 case BPF_KPTR_PERCPU:
3538 case BPF_UPTR:
3539 case BPF_LIST_HEAD:
3540 case BPF_RB_ROOT:
3541 break;
3542 default:
3543 return -EINVAL;
3544 }
3545 }
3546
3547 /* The type of struct size or variable size is u32,
3548 * so the multiplication will not overflow.
3549 */
3550 if (field_cnt * (repeat_cnt + 1) > info_cnt)
3551 return -E2BIG;
3552
3553 cur = field_cnt;
3554 for (i = 0; i < repeat_cnt; i++) {
3555 memcpy(&info[cur], &info[0], field_cnt * sizeof(info[0]));
3556 for (j = 0; j < field_cnt; j++)
3557 info[cur++].off += (i + 1) * elem_size;
3558 }
3559
3560 return 0;
3561}
3562
3563static int btf_find_struct_field(const struct btf *btf,
3564 const struct btf_type *t, u32 field_mask,
3565 struct btf_field_info *info, int info_cnt,
3566 u32 level);
3567
3568/* Find special fields in the struct type of a field.
3569 *
3570 * This function is used to find fields of special types that is not a
3571 * global variable or a direct field of a struct type. It also handles the
3572 * repetition if it is the element type of an array.
3573 */
3574static int btf_find_nested_struct(const struct btf *btf, const struct btf_type *t,
3575 u32 off, u32 nelems,
3576 u32 field_mask, struct btf_field_info *info,
3577 int info_cnt, u32 level)
3578{
3579 int ret, err, i;
3580
3581 level++;
3582 if (level >= MAX_RESOLVE_DEPTH)
3583 return -E2BIG;
3584
3585 ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt, level);
3586
3587 if (ret <= 0)
3588 return ret;
3589
3590 /* Shift the offsets of the nested struct fields to the offsets
3591 * related to the container.
3592 */
3593 for (i = 0; i < ret; i++)
3594 info[i].off += off;
3595
3596 if (nelems > 1) {
3597 err = btf_repeat_fields(info, info_cnt, ret, nelems - 1, t->size);
3598 if (err == 0)
3599 ret *= nelems;
3600 else
3601 ret = err;
3602 }
3603
3604 return ret;
3605}
3606
3607static int btf_find_field_one(const struct btf *btf,
3608 const struct btf_type *var,
3609 const struct btf_type *var_type,
3610 int var_idx,
3611 u32 off, u32 expected_size,
3612 u32 field_mask, u32 *seen_mask,
3613 struct btf_field_info *info, int info_cnt,
3614 u32 level)
3615{
3616 int ret, align, sz, field_type;
3617 struct btf_field_info tmp;
3618 const struct btf_array *array;
3619 u32 i, nelems = 1;
3620
3621 /* Walk into array types to find the element type and the number of
3622 * elements in the (flattened) array.
3623 */
3624 for (i = 0; i < MAX_RESOLVE_DEPTH && btf_type_is_array(var_type); i++) {
3625 array = btf_array(var_type);
3626 nelems *= array->nelems;
3627 var_type = btf_type_by_id(btf, array->type);
3628 }
3629 if (i == MAX_RESOLVE_DEPTH)
3630 return -E2BIG;
3631 if (nelems == 0)
3632 return 0;
3633
3634 field_type = btf_get_field_type(btf, var_type,
3635 field_mask, seen_mask, &align, &sz);
3636 /* Look into variables of struct types */
3637 if (!field_type && __btf_type_is_struct(var_type)) {
3638 sz = var_type->size;
3639 if (expected_size && expected_size != sz * nelems)
3640 return 0;
3641 ret = btf_find_nested_struct(btf, var_type, off, nelems, field_mask,
3642 &info[0], info_cnt, level);
3643 return ret;
3644 }
3645
3646 if (field_type == 0)
3647 return 0;
3648 if (field_type < 0)
3649 return field_type;
3650
3651 if (expected_size && expected_size != sz * nelems)
3652 return 0;
3653 if (off % align)
3654 return 0;
3655
3656 switch (field_type) {
3657 case BPF_SPIN_LOCK:
3658 case BPF_TIMER:
3659 case BPF_WORKQUEUE:
3660 case BPF_LIST_NODE:
3661 case BPF_RB_NODE:
3662 case BPF_REFCOUNT:
3663 ret = btf_find_struct(btf, var_type, off, sz, field_type,
3664 info_cnt ? &info[0] : &tmp);
3665 if (ret < 0)
3666 return ret;
3667 break;
3668 case BPF_KPTR_UNREF:
3669 case BPF_KPTR_REF:
3670 case BPF_KPTR_PERCPU:
3671 case BPF_UPTR:
3672 ret = btf_find_kptr(btf, var_type, off, sz,
3673 info_cnt ? &info[0] : &tmp, field_mask);
3674 if (ret < 0)
3675 return ret;
3676 break;
3677 case BPF_LIST_HEAD:
3678 case BPF_RB_ROOT:
3679 ret = btf_find_graph_root(btf, var, var_type,
3680 var_idx, off, sz,
3681 info_cnt ? &info[0] : &tmp,
3682 field_type);
3683 if (ret < 0)
3684 return ret;
3685 break;
3686 default:
3687 return -EFAULT;
3688 }
3689
3690 if (ret == BTF_FIELD_IGNORE)
3691 return 0;
3692 if (!info_cnt)
3693 return -E2BIG;
3694 if (nelems > 1) {
3695 ret = btf_repeat_fields(info, info_cnt, 1, nelems - 1, sz);
3696 if (ret < 0)
3697 return ret;
3698 }
3699 return nelems;
3700}
3701
3702static int btf_find_struct_field(const struct btf *btf,
3703 const struct btf_type *t, u32 field_mask,
3704 struct btf_field_info *info, int info_cnt,
3705 u32 level)
3706{
3707 int ret, idx = 0;
3708 const struct btf_member *member;
3709 u32 i, off, seen_mask = 0;
3710
3711 for_each_member(i, t, member) {
3712 const struct btf_type *member_type = btf_type_by_id(btf,
3713 member->type);
3714
3715 off = __btf_member_bit_offset(t, member);
3716 if (off % 8)
3717 /* valid C code cannot generate such BTF */
3718 return -EINVAL;
3719 off /= 8;
3720
3721 ret = btf_find_field_one(btf, t, member_type, i,
3722 off, 0,
3723 field_mask, &seen_mask,
3724 &info[idx], info_cnt - idx, level);
3725 if (ret < 0)
3726 return ret;
3727 idx += ret;
3728 }
3729 return idx;
3730}
3731
3732static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3733 u32 field_mask, struct btf_field_info *info,
3734 int info_cnt, u32 level)
3735{
3736 int ret, idx = 0;
3737 const struct btf_var_secinfo *vsi;
3738 u32 i, off, seen_mask = 0;
3739
3740 for_each_vsi(i, t, vsi) {
3741 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3742 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3743
3744 off = vsi->offset;
3745 ret = btf_find_field_one(btf, var, var_type, -1, off, vsi->size,
3746 field_mask, &seen_mask,
3747 &info[idx], info_cnt - idx,
3748 level);
3749 if (ret < 0)
3750 return ret;
3751 idx += ret;
3752 }
3753 return idx;
3754}
3755
3756static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3757 u32 field_mask, struct btf_field_info *info,
3758 int info_cnt)
3759{
3760 if (__btf_type_is_struct(t))
3761 return btf_find_struct_field(btf, t, field_mask, info, info_cnt, 0);
3762 else if (btf_type_is_datasec(t))
3763 return btf_find_datasec_var(btf, t, field_mask, info, info_cnt, 0);
3764 return -EINVAL;
3765}
3766
3767/* Callers have to ensure the life cycle of btf if it is program BTF */
3768static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3769 struct btf_field_info *info)
3770{
3771 struct module *mod = NULL;
3772 const struct btf_type *t;
3773 /* If a matching btf type is found in kernel or module BTFs, kptr_ref
3774 * is that BTF, otherwise it's program BTF
3775 */
3776 struct btf *kptr_btf;
3777 int ret;
3778 s32 id;
3779
3780 /* Find type in map BTF, and use it to look up the matching type
3781 * in vmlinux or module BTFs, by name and kind.
3782 */
3783 t = btf_type_by_id(btf, info->kptr.type_id);
3784 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3785 &kptr_btf);
3786 if (id == -ENOENT) {
3787 /* btf_parse_kptr should only be called w/ btf = program BTF */
3788 WARN_ON_ONCE(btf_is_kernel(btf));
3789
3790 /* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3791 * kptr allocated via bpf_obj_new
3792 */
3793 field->kptr.dtor = NULL;
3794 id = info->kptr.type_id;
3795 kptr_btf = (struct btf *)btf;
3796 goto found_dtor;
3797 }
3798 if (id < 0)
3799 return id;
3800
3801 /* Find and stash the function pointer for the destruction function that
3802 * needs to be eventually invoked from the map free path.
3803 */
3804 if (info->type == BPF_KPTR_REF) {
3805 const struct btf_type *dtor_func;
3806 const char *dtor_func_name;
3807 unsigned long addr;
3808 s32 dtor_btf_id;
3809
3810 /* This call also serves as a whitelist of allowed objects that
3811 * can be used as a referenced pointer and be stored in a map at
3812 * the same time.
3813 */
3814 dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3815 if (dtor_btf_id < 0) {
3816 ret = dtor_btf_id;
3817 goto end_btf;
3818 }
3819
3820 dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3821 if (!dtor_func) {
3822 ret = -ENOENT;
3823 goto end_btf;
3824 }
3825
3826 if (btf_is_module(kptr_btf)) {
3827 mod = btf_try_get_module(kptr_btf);
3828 if (!mod) {
3829 ret = -ENXIO;
3830 goto end_btf;
3831 }
3832 }
3833
3834 /* We already verified dtor_func to be btf_type_is_func
3835 * in register_btf_id_dtor_kfuncs.
3836 */
3837 dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3838 addr = kallsyms_lookup_name(dtor_func_name);
3839 if (!addr) {
3840 ret = -EINVAL;
3841 goto end_mod;
3842 }
3843 field->kptr.dtor = (void *)addr;
3844 }
3845
3846found_dtor:
3847 field->kptr.btf_id = id;
3848 field->kptr.btf = kptr_btf;
3849 field->kptr.module = mod;
3850 return 0;
3851end_mod:
3852 module_put(mod);
3853end_btf:
3854 btf_put(kptr_btf);
3855 return ret;
3856}
3857
3858static int btf_parse_graph_root(const struct btf *btf,
3859 struct btf_field *field,
3860 struct btf_field_info *info,
3861 const char *node_type_name,
3862 size_t node_type_align)
3863{
3864 const struct btf_type *t, *n = NULL;
3865 const struct btf_member *member;
3866 u32 offset;
3867 int i;
3868
3869 t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3870 /* We've already checked that value_btf_id is a struct type. We
3871 * just need to figure out the offset of the list_node, and
3872 * verify its type.
3873 */
3874 for_each_member(i, t, member) {
3875 if (strcmp(info->graph_root.node_name,
3876 __btf_name_by_offset(btf, member->name_off)))
3877 continue;
3878 /* Invalid BTF, two members with same name */
3879 if (n)
3880 return -EINVAL;
3881 n = btf_type_by_id(btf, member->type);
3882 if (!__btf_type_is_struct(n))
3883 return -EINVAL;
3884 if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3885 return -EINVAL;
3886 offset = __btf_member_bit_offset(n, member);
3887 if (offset % 8)
3888 return -EINVAL;
3889 offset /= 8;
3890 if (offset % node_type_align)
3891 return -EINVAL;
3892
3893 field->graph_root.btf = (struct btf *)btf;
3894 field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3895 field->graph_root.node_offset = offset;
3896 }
3897 if (!n)
3898 return -ENOENT;
3899 return 0;
3900}
3901
3902static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3903 struct btf_field_info *info)
3904{
3905 return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3906 __alignof__(struct bpf_list_node));
3907}
3908
3909static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3910 struct btf_field_info *info)
3911{
3912 return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3913 __alignof__(struct bpf_rb_node));
3914}
3915
3916static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3917{
3918 const struct btf_field *a = (const struct btf_field *)_a;
3919 const struct btf_field *b = (const struct btf_field *)_b;
3920
3921 if (a->offset < b->offset)
3922 return -1;
3923 else if (a->offset > b->offset)
3924 return 1;
3925 return 0;
3926}
3927
3928struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3929 u32 field_mask, u32 value_size)
3930{
3931 struct btf_field_info info_arr[BTF_FIELDS_MAX];
3932 u32 next_off = 0, field_type_size;
3933 struct btf_record *rec;
3934 int ret, i, cnt;
3935
3936 ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3937 if (ret < 0)
3938 return ERR_PTR(ret);
3939 if (!ret)
3940 return NULL;
3941
3942 cnt = ret;
3943 /* This needs to be kzalloc to zero out padding and unused fields, see
3944 * comment in btf_record_equal.
3945 */
3946 rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3947 if (!rec)
3948 return ERR_PTR(-ENOMEM);
3949
3950 rec->spin_lock_off = -EINVAL;
3951 rec->timer_off = -EINVAL;
3952 rec->wq_off = -EINVAL;
3953 rec->refcount_off = -EINVAL;
3954 for (i = 0; i < cnt; i++) {
3955 field_type_size = btf_field_type_size(info_arr[i].type);
3956 if (info_arr[i].off + field_type_size > value_size) {
3957 WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3958 ret = -EFAULT;
3959 goto end;
3960 }
3961 if (info_arr[i].off < next_off) {
3962 ret = -EEXIST;
3963 goto end;
3964 }
3965 next_off = info_arr[i].off + field_type_size;
3966
3967 rec->field_mask |= info_arr[i].type;
3968 rec->fields[i].offset = info_arr[i].off;
3969 rec->fields[i].type = info_arr[i].type;
3970 rec->fields[i].size = field_type_size;
3971
3972 switch (info_arr[i].type) {
3973 case BPF_SPIN_LOCK:
3974 WARN_ON_ONCE(rec->spin_lock_off >= 0);
3975 /* Cache offset for faster lookup at runtime */
3976 rec->spin_lock_off = rec->fields[i].offset;
3977 break;
3978 case BPF_TIMER:
3979 WARN_ON_ONCE(rec->timer_off >= 0);
3980 /* Cache offset for faster lookup at runtime */
3981 rec->timer_off = rec->fields[i].offset;
3982 break;
3983 case BPF_WORKQUEUE:
3984 WARN_ON_ONCE(rec->wq_off >= 0);
3985 /* Cache offset for faster lookup at runtime */
3986 rec->wq_off = rec->fields[i].offset;
3987 break;
3988 case BPF_REFCOUNT:
3989 WARN_ON_ONCE(rec->refcount_off >= 0);
3990 /* Cache offset for faster lookup at runtime */
3991 rec->refcount_off = rec->fields[i].offset;
3992 break;
3993 case BPF_KPTR_UNREF:
3994 case BPF_KPTR_REF:
3995 case BPF_KPTR_PERCPU:
3996 case BPF_UPTR:
3997 ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3998 if (ret < 0)
3999 goto end;
4000 break;
4001 case BPF_LIST_HEAD:
4002 ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
4003 if (ret < 0)
4004 goto end;
4005 break;
4006 case BPF_RB_ROOT:
4007 ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
4008 if (ret < 0)
4009 goto end;
4010 break;
4011 case BPF_LIST_NODE:
4012 case BPF_RB_NODE:
4013 break;
4014 default:
4015 ret = -EFAULT;
4016 goto end;
4017 }
4018 rec->cnt++;
4019 }
4020
4021 /* bpf_{list_head, rb_node} require bpf_spin_lock */
4022 if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
4023 btf_record_has_field(rec, BPF_RB_ROOT)) && rec->spin_lock_off < 0) {
4024 ret = -EINVAL;
4025 goto end;
4026 }
4027
4028 if (rec->refcount_off < 0 &&
4029 btf_record_has_field(rec, BPF_LIST_NODE) &&
4030 btf_record_has_field(rec, BPF_RB_NODE)) {
4031 ret = -EINVAL;
4032 goto end;
4033 }
4034
4035 sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
4036 NULL, rec);
4037
4038 return rec;
4039end:
4040 btf_record_free(rec);
4041 return ERR_PTR(ret);
4042}
4043
4044int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
4045{
4046 int i;
4047
4048 /* There are three types that signify ownership of some other type:
4049 * kptr_ref, bpf_list_head, bpf_rb_root.
4050 * kptr_ref only supports storing kernel types, which can't store
4051 * references to program allocated local types.
4052 *
4053 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
4054 * does not form cycles.
4055 */
4056 if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & (BPF_GRAPH_ROOT | BPF_UPTR)))
4057 return 0;
4058 for (i = 0; i < rec->cnt; i++) {
4059 struct btf_struct_meta *meta;
4060 const struct btf_type *t;
4061 u32 btf_id;
4062
4063 if (rec->fields[i].type == BPF_UPTR) {
4064 /* The uptr only supports pinning one page and cannot
4065 * point to a kernel struct
4066 */
4067 if (btf_is_kernel(rec->fields[i].kptr.btf))
4068 return -EINVAL;
4069 t = btf_type_by_id(rec->fields[i].kptr.btf,
4070 rec->fields[i].kptr.btf_id);
4071 if (!t->size)
4072 return -EINVAL;
4073 if (t->size > PAGE_SIZE)
4074 return -E2BIG;
4075 continue;
4076 }
4077
4078 if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
4079 continue;
4080 btf_id = rec->fields[i].graph_root.value_btf_id;
4081 meta = btf_find_struct_meta(btf, btf_id);
4082 if (!meta)
4083 return -EFAULT;
4084 rec->fields[i].graph_root.value_rec = meta->record;
4085
4086 /* We need to set value_rec for all root types, but no need
4087 * to check ownership cycle for a type unless it's also a
4088 * node type.
4089 */
4090 if (!(rec->field_mask & BPF_GRAPH_NODE))
4091 continue;
4092
4093 /* We need to ensure ownership acyclicity among all types. The
4094 * proper way to do it would be to topologically sort all BTF
4095 * IDs based on the ownership edges, since there can be multiple
4096 * bpf_{list_head,rb_node} in a type. Instead, we use the
4097 * following resaoning:
4098 *
4099 * - A type can only be owned by another type in user BTF if it
4100 * has a bpf_{list,rb}_node. Let's call these node types.
4101 * - A type can only _own_ another type in user BTF if it has a
4102 * bpf_{list_head,rb_root}. Let's call these root types.
4103 *
4104 * We ensure that if a type is both a root and node, its
4105 * element types cannot be root types.
4106 *
4107 * To ensure acyclicity:
4108 *
4109 * When A is an root type but not a node, its ownership
4110 * chain can be:
4111 * A -> B -> C
4112 * Where:
4113 * - A is an root, e.g. has bpf_rb_root.
4114 * - B is both a root and node, e.g. has bpf_rb_node and
4115 * bpf_list_head.
4116 * - C is only an root, e.g. has bpf_list_node
4117 *
4118 * When A is both a root and node, some other type already
4119 * owns it in the BTF domain, hence it can not own
4120 * another root type through any of the ownership edges.
4121 * A -> B
4122 * Where:
4123 * - A is both an root and node.
4124 * - B is only an node.
4125 */
4126 if (meta->record->field_mask & BPF_GRAPH_ROOT)
4127 return -ELOOP;
4128 }
4129 return 0;
4130}
4131
4132static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
4133 u32 type_id, void *data, u8 bits_offset,
4134 struct btf_show *show)
4135{
4136 const struct btf_member *member;
4137 void *safe_data;
4138 u32 i;
4139
4140 safe_data = btf_show_start_struct_type(show, t, type_id, data);
4141 if (!safe_data)
4142 return;
4143
4144 for_each_member(i, t, member) {
4145 const struct btf_type *member_type = btf_type_by_id(btf,
4146 member->type);
4147 const struct btf_kind_operations *ops;
4148 u32 member_offset, bitfield_size;
4149 u32 bytes_offset;
4150 u8 bits8_offset;
4151
4152 btf_show_start_member(show, member);
4153
4154 member_offset = __btf_member_bit_offset(t, member);
4155 bitfield_size = __btf_member_bitfield_size(t, member);
4156 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
4157 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
4158 if (bitfield_size) {
4159 safe_data = btf_show_start_type(show, member_type,
4160 member->type,
4161 data + bytes_offset);
4162 if (safe_data)
4163 btf_bitfield_show(safe_data,
4164 bits8_offset,
4165 bitfield_size, show);
4166 btf_show_end_type(show);
4167 } else {
4168 ops = btf_type_ops(member_type);
4169 ops->show(btf, member_type, member->type,
4170 data + bytes_offset, bits8_offset, show);
4171 }
4172
4173 btf_show_end_member(show);
4174 }
4175
4176 btf_show_end_struct_type(show);
4177}
4178
4179static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
4180 u32 type_id, void *data, u8 bits_offset,
4181 struct btf_show *show)
4182{
4183 const struct btf_member *m = show->state.member;
4184
4185 /*
4186 * First check if any members would be shown (are non-zero).
4187 * See comments above "struct btf_show" definition for more
4188 * details on how this works at a high-level.
4189 */
4190 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
4191 if (!show->state.depth_check) {
4192 show->state.depth_check = show->state.depth + 1;
4193 show->state.depth_to_show = 0;
4194 }
4195 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4196 /* Restore saved member data here */
4197 show->state.member = m;
4198 if (show->state.depth_check != show->state.depth + 1)
4199 return;
4200 show->state.depth_check = 0;
4201
4202 if (show->state.depth_to_show <= show->state.depth)
4203 return;
4204 /*
4205 * Reaching here indicates we have recursed and found
4206 * non-zero child values.
4207 */
4208 }
4209
4210 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
4211}
4212
4213static const struct btf_kind_operations struct_ops = {
4214 .check_meta = btf_struct_check_meta,
4215 .resolve = btf_struct_resolve,
4216 .check_member = btf_struct_check_member,
4217 .check_kflag_member = btf_generic_check_kflag_member,
4218 .log_details = btf_struct_log,
4219 .show = btf_struct_show,
4220};
4221
4222static int btf_enum_check_member(struct btf_verifier_env *env,
4223 const struct btf_type *struct_type,
4224 const struct btf_member *member,
4225 const struct btf_type *member_type)
4226{
4227 u32 struct_bits_off = member->offset;
4228 u32 struct_size, bytes_offset;
4229
4230 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4231 btf_verifier_log_member(env, struct_type, member,
4232 "Member is not byte aligned");
4233 return -EINVAL;
4234 }
4235
4236 struct_size = struct_type->size;
4237 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4238 if (struct_size - bytes_offset < member_type->size) {
4239 btf_verifier_log_member(env, struct_type, member,
4240 "Member exceeds struct_size");
4241 return -EINVAL;
4242 }
4243
4244 return 0;
4245}
4246
4247static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4248 const struct btf_type *struct_type,
4249 const struct btf_member *member,
4250 const struct btf_type *member_type)
4251{
4252 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4253 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4254
4255 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4256 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4257 if (!nr_bits) {
4258 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4259 btf_verifier_log_member(env, struct_type, member,
4260 "Member is not byte aligned");
4261 return -EINVAL;
4262 }
4263
4264 nr_bits = int_bitsize;
4265 } else if (nr_bits > int_bitsize) {
4266 btf_verifier_log_member(env, struct_type, member,
4267 "Invalid member bitfield_size");
4268 return -EINVAL;
4269 }
4270
4271 struct_size = struct_type->size;
4272 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4273 if (struct_size < bytes_end) {
4274 btf_verifier_log_member(env, struct_type, member,
4275 "Member exceeds struct_size");
4276 return -EINVAL;
4277 }
4278
4279 return 0;
4280}
4281
4282static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4283 const struct btf_type *t,
4284 u32 meta_left)
4285{
4286 const struct btf_enum *enums = btf_type_enum(t);
4287 struct btf *btf = env->btf;
4288 const char *fmt_str;
4289 u16 i, nr_enums;
4290 u32 meta_needed;
4291
4292 nr_enums = btf_type_vlen(t);
4293 meta_needed = nr_enums * sizeof(*enums);
4294
4295 if (meta_left < meta_needed) {
4296 btf_verifier_log_basic(env, t,
4297 "meta_left:%u meta_needed:%u",
4298 meta_left, meta_needed);
4299 return -EINVAL;
4300 }
4301
4302 if (t->size > 8 || !is_power_of_2(t->size)) {
4303 btf_verifier_log_type(env, t, "Unexpected size");
4304 return -EINVAL;
4305 }
4306
4307 /* enum type either no name or a valid one */
4308 if (t->name_off &&
4309 !btf_name_valid_identifier(env->btf, t->name_off)) {
4310 btf_verifier_log_type(env, t, "Invalid name");
4311 return -EINVAL;
4312 }
4313
4314 btf_verifier_log_type(env, t, NULL);
4315
4316 for (i = 0; i < nr_enums; i++) {
4317 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4318 btf_verifier_log(env, "\tInvalid name_offset:%u",
4319 enums[i].name_off);
4320 return -EINVAL;
4321 }
4322
4323 /* enum member must have a valid name */
4324 if (!enums[i].name_off ||
4325 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4326 btf_verifier_log_type(env, t, "Invalid name");
4327 return -EINVAL;
4328 }
4329
4330 if (env->log.level == BPF_LOG_KERNEL)
4331 continue;
4332 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4333 btf_verifier_log(env, fmt_str,
4334 __btf_name_by_offset(btf, enums[i].name_off),
4335 enums[i].val);
4336 }
4337
4338 return meta_needed;
4339}
4340
4341static void btf_enum_log(struct btf_verifier_env *env,
4342 const struct btf_type *t)
4343{
4344 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4345}
4346
4347static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4348 u32 type_id, void *data, u8 bits_offset,
4349 struct btf_show *show)
4350{
4351 const struct btf_enum *enums = btf_type_enum(t);
4352 u32 i, nr_enums = btf_type_vlen(t);
4353 void *safe_data;
4354 int v;
4355
4356 safe_data = btf_show_start_type(show, t, type_id, data);
4357 if (!safe_data)
4358 return;
4359
4360 v = *(int *)safe_data;
4361
4362 for (i = 0; i < nr_enums; i++) {
4363 if (v != enums[i].val)
4364 continue;
4365
4366 btf_show_type_value(show, "%s",
4367 __btf_name_by_offset(btf,
4368 enums[i].name_off));
4369
4370 btf_show_end_type(show);
4371 return;
4372 }
4373
4374 if (btf_type_kflag(t))
4375 btf_show_type_value(show, "%d", v);
4376 else
4377 btf_show_type_value(show, "%u", v);
4378 btf_show_end_type(show);
4379}
4380
4381static const struct btf_kind_operations enum_ops = {
4382 .check_meta = btf_enum_check_meta,
4383 .resolve = btf_df_resolve,
4384 .check_member = btf_enum_check_member,
4385 .check_kflag_member = btf_enum_check_kflag_member,
4386 .log_details = btf_enum_log,
4387 .show = btf_enum_show,
4388};
4389
4390static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4391 const struct btf_type *t,
4392 u32 meta_left)
4393{
4394 const struct btf_enum64 *enums = btf_type_enum64(t);
4395 struct btf *btf = env->btf;
4396 const char *fmt_str;
4397 u16 i, nr_enums;
4398 u32 meta_needed;
4399
4400 nr_enums = btf_type_vlen(t);
4401 meta_needed = nr_enums * sizeof(*enums);
4402
4403 if (meta_left < meta_needed) {
4404 btf_verifier_log_basic(env, t,
4405 "meta_left:%u meta_needed:%u",
4406 meta_left, meta_needed);
4407 return -EINVAL;
4408 }
4409
4410 if (t->size > 8 || !is_power_of_2(t->size)) {
4411 btf_verifier_log_type(env, t, "Unexpected size");
4412 return -EINVAL;
4413 }
4414
4415 /* enum type either no name or a valid one */
4416 if (t->name_off &&
4417 !btf_name_valid_identifier(env->btf, t->name_off)) {
4418 btf_verifier_log_type(env, t, "Invalid name");
4419 return -EINVAL;
4420 }
4421
4422 btf_verifier_log_type(env, t, NULL);
4423
4424 for (i = 0; i < nr_enums; i++) {
4425 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4426 btf_verifier_log(env, "\tInvalid name_offset:%u",
4427 enums[i].name_off);
4428 return -EINVAL;
4429 }
4430
4431 /* enum member must have a valid name */
4432 if (!enums[i].name_off ||
4433 !btf_name_valid_identifier(btf, enums[i].name_off)) {
4434 btf_verifier_log_type(env, t, "Invalid name");
4435 return -EINVAL;
4436 }
4437
4438 if (env->log.level == BPF_LOG_KERNEL)
4439 continue;
4440
4441 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4442 btf_verifier_log(env, fmt_str,
4443 __btf_name_by_offset(btf, enums[i].name_off),
4444 btf_enum64_value(enums + i));
4445 }
4446
4447 return meta_needed;
4448}
4449
4450static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4451 u32 type_id, void *data, u8 bits_offset,
4452 struct btf_show *show)
4453{
4454 const struct btf_enum64 *enums = btf_type_enum64(t);
4455 u32 i, nr_enums = btf_type_vlen(t);
4456 void *safe_data;
4457 s64 v;
4458
4459 safe_data = btf_show_start_type(show, t, type_id, data);
4460 if (!safe_data)
4461 return;
4462
4463 v = *(u64 *)safe_data;
4464
4465 for (i = 0; i < nr_enums; i++) {
4466 if (v != btf_enum64_value(enums + i))
4467 continue;
4468
4469 btf_show_type_value(show, "%s",
4470 __btf_name_by_offset(btf,
4471 enums[i].name_off));
4472
4473 btf_show_end_type(show);
4474 return;
4475 }
4476
4477 if (btf_type_kflag(t))
4478 btf_show_type_value(show, "%lld", v);
4479 else
4480 btf_show_type_value(show, "%llu", v);
4481 btf_show_end_type(show);
4482}
4483
4484static const struct btf_kind_operations enum64_ops = {
4485 .check_meta = btf_enum64_check_meta,
4486 .resolve = btf_df_resolve,
4487 .check_member = btf_enum_check_member,
4488 .check_kflag_member = btf_enum_check_kflag_member,
4489 .log_details = btf_enum_log,
4490 .show = btf_enum64_show,
4491};
4492
4493static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4494 const struct btf_type *t,
4495 u32 meta_left)
4496{
4497 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4498
4499 if (meta_left < meta_needed) {
4500 btf_verifier_log_basic(env, t,
4501 "meta_left:%u meta_needed:%u",
4502 meta_left, meta_needed);
4503 return -EINVAL;
4504 }
4505
4506 if (t->name_off) {
4507 btf_verifier_log_type(env, t, "Invalid name");
4508 return -EINVAL;
4509 }
4510
4511 if (btf_type_kflag(t)) {
4512 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4513 return -EINVAL;
4514 }
4515
4516 btf_verifier_log_type(env, t, NULL);
4517
4518 return meta_needed;
4519}
4520
4521static void btf_func_proto_log(struct btf_verifier_env *env,
4522 const struct btf_type *t)
4523{
4524 const struct btf_param *args = (const struct btf_param *)(t + 1);
4525 u16 nr_args = btf_type_vlen(t), i;
4526
4527 btf_verifier_log(env, "return=%u args=(", t->type);
4528 if (!nr_args) {
4529 btf_verifier_log(env, "void");
4530 goto done;
4531 }
4532
4533 if (nr_args == 1 && !args[0].type) {
4534 /* Only one vararg */
4535 btf_verifier_log(env, "vararg");
4536 goto done;
4537 }
4538
4539 btf_verifier_log(env, "%u %s", args[0].type,
4540 __btf_name_by_offset(env->btf,
4541 args[0].name_off));
4542 for (i = 1; i < nr_args - 1; i++)
4543 btf_verifier_log(env, ", %u %s", args[i].type,
4544 __btf_name_by_offset(env->btf,
4545 args[i].name_off));
4546
4547 if (nr_args > 1) {
4548 const struct btf_param *last_arg = &args[nr_args - 1];
4549
4550 if (last_arg->type)
4551 btf_verifier_log(env, ", %u %s", last_arg->type,
4552 __btf_name_by_offset(env->btf,
4553 last_arg->name_off));
4554 else
4555 btf_verifier_log(env, ", vararg");
4556 }
4557
4558done:
4559 btf_verifier_log(env, ")");
4560}
4561
4562static const struct btf_kind_operations func_proto_ops = {
4563 .check_meta = btf_func_proto_check_meta,
4564 .resolve = btf_df_resolve,
4565 /*
4566 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4567 * a struct's member.
4568 *
4569 * It should be a function pointer instead.
4570 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4571 *
4572 * Hence, there is no btf_func_check_member().
4573 */
4574 .check_member = btf_df_check_member,
4575 .check_kflag_member = btf_df_check_kflag_member,
4576 .log_details = btf_func_proto_log,
4577 .show = btf_df_show,
4578};
4579
4580static s32 btf_func_check_meta(struct btf_verifier_env *env,
4581 const struct btf_type *t,
4582 u32 meta_left)
4583{
4584 if (!t->name_off ||
4585 !btf_name_valid_identifier(env->btf, t->name_off)) {
4586 btf_verifier_log_type(env, t, "Invalid name");
4587 return -EINVAL;
4588 }
4589
4590 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4591 btf_verifier_log_type(env, t, "Invalid func linkage");
4592 return -EINVAL;
4593 }
4594
4595 if (btf_type_kflag(t)) {
4596 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4597 return -EINVAL;
4598 }
4599
4600 btf_verifier_log_type(env, t, NULL);
4601
4602 return 0;
4603}
4604
4605static int btf_func_resolve(struct btf_verifier_env *env,
4606 const struct resolve_vertex *v)
4607{
4608 const struct btf_type *t = v->t;
4609 u32 next_type_id = t->type;
4610 int err;
4611
4612 err = btf_func_check(env, t);
4613 if (err)
4614 return err;
4615
4616 env_stack_pop_resolved(env, next_type_id, 0);
4617 return 0;
4618}
4619
4620static const struct btf_kind_operations func_ops = {
4621 .check_meta = btf_func_check_meta,
4622 .resolve = btf_func_resolve,
4623 .check_member = btf_df_check_member,
4624 .check_kflag_member = btf_df_check_kflag_member,
4625 .log_details = btf_ref_type_log,
4626 .show = btf_df_show,
4627};
4628
4629static s32 btf_var_check_meta(struct btf_verifier_env *env,
4630 const struct btf_type *t,
4631 u32 meta_left)
4632{
4633 const struct btf_var *var;
4634 u32 meta_needed = sizeof(*var);
4635
4636 if (meta_left < meta_needed) {
4637 btf_verifier_log_basic(env, t,
4638 "meta_left:%u meta_needed:%u",
4639 meta_left, meta_needed);
4640 return -EINVAL;
4641 }
4642
4643 if (btf_type_vlen(t)) {
4644 btf_verifier_log_type(env, t, "vlen != 0");
4645 return -EINVAL;
4646 }
4647
4648 if (btf_type_kflag(t)) {
4649 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4650 return -EINVAL;
4651 }
4652
4653 if (!t->name_off ||
4654 !btf_name_valid_identifier(env->btf, t->name_off)) {
4655 btf_verifier_log_type(env, t, "Invalid name");
4656 return -EINVAL;
4657 }
4658
4659 /* A var cannot be in type void */
4660 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4661 btf_verifier_log_type(env, t, "Invalid type_id");
4662 return -EINVAL;
4663 }
4664
4665 var = btf_type_var(t);
4666 if (var->linkage != BTF_VAR_STATIC &&
4667 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4668 btf_verifier_log_type(env, t, "Linkage not supported");
4669 return -EINVAL;
4670 }
4671
4672 btf_verifier_log_type(env, t, NULL);
4673
4674 return meta_needed;
4675}
4676
4677static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4678{
4679 const struct btf_var *var = btf_type_var(t);
4680
4681 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4682}
4683
4684static const struct btf_kind_operations var_ops = {
4685 .check_meta = btf_var_check_meta,
4686 .resolve = btf_var_resolve,
4687 .check_member = btf_df_check_member,
4688 .check_kflag_member = btf_df_check_kflag_member,
4689 .log_details = btf_var_log,
4690 .show = btf_var_show,
4691};
4692
4693static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4694 const struct btf_type *t,
4695 u32 meta_left)
4696{
4697 const struct btf_var_secinfo *vsi;
4698 u64 last_vsi_end_off = 0, sum = 0;
4699 u32 i, meta_needed;
4700
4701 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4702 if (meta_left < meta_needed) {
4703 btf_verifier_log_basic(env, t,
4704 "meta_left:%u meta_needed:%u",
4705 meta_left, meta_needed);
4706 return -EINVAL;
4707 }
4708
4709 if (!t->size) {
4710 btf_verifier_log_type(env, t, "size == 0");
4711 return -EINVAL;
4712 }
4713
4714 if (btf_type_kflag(t)) {
4715 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4716 return -EINVAL;
4717 }
4718
4719 if (!t->name_off ||
4720 !btf_name_valid_section(env->btf, t->name_off)) {
4721 btf_verifier_log_type(env, t, "Invalid name");
4722 return -EINVAL;
4723 }
4724
4725 btf_verifier_log_type(env, t, NULL);
4726
4727 for_each_vsi(i, t, vsi) {
4728 /* A var cannot be in type void */
4729 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4730 btf_verifier_log_vsi(env, t, vsi,
4731 "Invalid type_id");
4732 return -EINVAL;
4733 }
4734
4735 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4736 btf_verifier_log_vsi(env, t, vsi,
4737 "Invalid offset");
4738 return -EINVAL;
4739 }
4740
4741 if (!vsi->size || vsi->size > t->size) {
4742 btf_verifier_log_vsi(env, t, vsi,
4743 "Invalid size");
4744 return -EINVAL;
4745 }
4746
4747 last_vsi_end_off = vsi->offset + vsi->size;
4748 if (last_vsi_end_off > t->size) {
4749 btf_verifier_log_vsi(env, t, vsi,
4750 "Invalid offset+size");
4751 return -EINVAL;
4752 }
4753
4754 btf_verifier_log_vsi(env, t, vsi, NULL);
4755 sum += vsi->size;
4756 }
4757
4758 if (t->size < sum) {
4759 btf_verifier_log_type(env, t, "Invalid btf_info size");
4760 return -EINVAL;
4761 }
4762
4763 return meta_needed;
4764}
4765
4766static int btf_datasec_resolve(struct btf_verifier_env *env,
4767 const struct resolve_vertex *v)
4768{
4769 const struct btf_var_secinfo *vsi;
4770 struct btf *btf = env->btf;
4771 u16 i;
4772
4773 env->resolve_mode = RESOLVE_TBD;
4774 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4775 u32 var_type_id = vsi->type, type_id, type_size = 0;
4776 const struct btf_type *var_type = btf_type_by_id(env->btf,
4777 var_type_id);
4778 if (!var_type || !btf_type_is_var(var_type)) {
4779 btf_verifier_log_vsi(env, v->t, vsi,
4780 "Not a VAR kind member");
4781 return -EINVAL;
4782 }
4783
4784 if (!env_type_is_resolve_sink(env, var_type) &&
4785 !env_type_is_resolved(env, var_type_id)) {
4786 env_stack_set_next_member(env, i + 1);
4787 return env_stack_push(env, var_type, var_type_id);
4788 }
4789
4790 type_id = var_type->type;
4791 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4792 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4793 return -EINVAL;
4794 }
4795
4796 if (vsi->size < type_size) {
4797 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4798 return -EINVAL;
4799 }
4800 }
4801
4802 env_stack_pop_resolved(env, 0, 0);
4803 return 0;
4804}
4805
4806static void btf_datasec_log(struct btf_verifier_env *env,
4807 const struct btf_type *t)
4808{
4809 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4810}
4811
4812static void btf_datasec_show(const struct btf *btf,
4813 const struct btf_type *t, u32 type_id,
4814 void *data, u8 bits_offset,
4815 struct btf_show *show)
4816{
4817 const struct btf_var_secinfo *vsi;
4818 const struct btf_type *var;
4819 u32 i;
4820
4821 if (!btf_show_start_type(show, t, type_id, data))
4822 return;
4823
4824 btf_show_type_value(show, "section (\"%s\") = {",
4825 __btf_name_by_offset(btf, t->name_off));
4826 for_each_vsi(i, t, vsi) {
4827 var = btf_type_by_id(btf, vsi->type);
4828 if (i)
4829 btf_show(show, ",");
4830 btf_type_ops(var)->show(btf, var, vsi->type,
4831 data + vsi->offset, bits_offset, show);
4832 }
4833 btf_show_end_type(show);
4834}
4835
4836static const struct btf_kind_operations datasec_ops = {
4837 .check_meta = btf_datasec_check_meta,
4838 .resolve = btf_datasec_resolve,
4839 .check_member = btf_df_check_member,
4840 .check_kflag_member = btf_df_check_kflag_member,
4841 .log_details = btf_datasec_log,
4842 .show = btf_datasec_show,
4843};
4844
4845static s32 btf_float_check_meta(struct btf_verifier_env *env,
4846 const struct btf_type *t,
4847 u32 meta_left)
4848{
4849 if (btf_type_vlen(t)) {
4850 btf_verifier_log_type(env, t, "vlen != 0");
4851 return -EINVAL;
4852 }
4853
4854 if (btf_type_kflag(t)) {
4855 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4856 return -EINVAL;
4857 }
4858
4859 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4860 t->size != 16) {
4861 btf_verifier_log_type(env, t, "Invalid type_size");
4862 return -EINVAL;
4863 }
4864
4865 btf_verifier_log_type(env, t, NULL);
4866
4867 return 0;
4868}
4869
4870static int btf_float_check_member(struct btf_verifier_env *env,
4871 const struct btf_type *struct_type,
4872 const struct btf_member *member,
4873 const struct btf_type *member_type)
4874{
4875 u64 start_offset_bytes;
4876 u64 end_offset_bytes;
4877 u64 misalign_bits;
4878 u64 align_bytes;
4879 u64 align_bits;
4880
4881 /* Different architectures have different alignment requirements, so
4882 * here we check only for the reasonable minimum. This way we ensure
4883 * that types after CO-RE can pass the kernel BTF verifier.
4884 */
4885 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4886 align_bits = align_bytes * BITS_PER_BYTE;
4887 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4888 if (misalign_bits) {
4889 btf_verifier_log_member(env, struct_type, member,
4890 "Member is not properly aligned");
4891 return -EINVAL;
4892 }
4893
4894 start_offset_bytes = member->offset / BITS_PER_BYTE;
4895 end_offset_bytes = start_offset_bytes + member_type->size;
4896 if (end_offset_bytes > struct_type->size) {
4897 btf_verifier_log_member(env, struct_type, member,
4898 "Member exceeds struct_size");
4899 return -EINVAL;
4900 }
4901
4902 return 0;
4903}
4904
4905static void btf_float_log(struct btf_verifier_env *env,
4906 const struct btf_type *t)
4907{
4908 btf_verifier_log(env, "size=%u", t->size);
4909}
4910
4911static const struct btf_kind_operations float_ops = {
4912 .check_meta = btf_float_check_meta,
4913 .resolve = btf_df_resolve,
4914 .check_member = btf_float_check_member,
4915 .check_kflag_member = btf_generic_check_kflag_member,
4916 .log_details = btf_float_log,
4917 .show = btf_df_show,
4918};
4919
4920static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4921 const struct btf_type *t,
4922 u32 meta_left)
4923{
4924 const struct btf_decl_tag *tag;
4925 u32 meta_needed = sizeof(*tag);
4926 s32 component_idx;
4927 const char *value;
4928
4929 if (meta_left < meta_needed) {
4930 btf_verifier_log_basic(env, t,
4931 "meta_left:%u meta_needed:%u",
4932 meta_left, meta_needed);
4933 return -EINVAL;
4934 }
4935
4936 value = btf_name_by_offset(env->btf, t->name_off);
4937 if (!value || !value[0]) {
4938 btf_verifier_log_type(env, t, "Invalid value");
4939 return -EINVAL;
4940 }
4941
4942 if (btf_type_vlen(t)) {
4943 btf_verifier_log_type(env, t, "vlen != 0");
4944 return -EINVAL;
4945 }
4946
4947 if (btf_type_kflag(t)) {
4948 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4949 return -EINVAL;
4950 }
4951
4952 component_idx = btf_type_decl_tag(t)->component_idx;
4953 if (component_idx < -1) {
4954 btf_verifier_log_type(env, t, "Invalid component_idx");
4955 return -EINVAL;
4956 }
4957
4958 btf_verifier_log_type(env, t, NULL);
4959
4960 return meta_needed;
4961}
4962
4963static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4964 const struct resolve_vertex *v)
4965{
4966 const struct btf_type *next_type;
4967 const struct btf_type *t = v->t;
4968 u32 next_type_id = t->type;
4969 struct btf *btf = env->btf;
4970 s32 component_idx;
4971 u32 vlen;
4972
4973 next_type = btf_type_by_id(btf, next_type_id);
4974 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4975 btf_verifier_log_type(env, v->t, "Invalid type_id");
4976 return -EINVAL;
4977 }
4978
4979 if (!env_type_is_resolve_sink(env, next_type) &&
4980 !env_type_is_resolved(env, next_type_id))
4981 return env_stack_push(env, next_type, next_type_id);
4982
4983 component_idx = btf_type_decl_tag(t)->component_idx;
4984 if (component_idx != -1) {
4985 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4986 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4987 return -EINVAL;
4988 }
4989
4990 if (btf_type_is_struct(next_type)) {
4991 vlen = btf_type_vlen(next_type);
4992 } else {
4993 /* next_type should be a function */
4994 next_type = btf_type_by_id(btf, next_type->type);
4995 vlen = btf_type_vlen(next_type);
4996 }
4997
4998 if ((u32)component_idx >= vlen) {
4999 btf_verifier_log_type(env, v->t, "Invalid component_idx");
5000 return -EINVAL;
5001 }
5002 }
5003
5004 env_stack_pop_resolved(env, next_type_id, 0);
5005
5006 return 0;
5007}
5008
5009static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
5010{
5011 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
5012 btf_type_decl_tag(t)->component_idx);
5013}
5014
5015static const struct btf_kind_operations decl_tag_ops = {
5016 .check_meta = btf_decl_tag_check_meta,
5017 .resolve = btf_decl_tag_resolve,
5018 .check_member = btf_df_check_member,
5019 .check_kflag_member = btf_df_check_kflag_member,
5020 .log_details = btf_decl_tag_log,
5021 .show = btf_df_show,
5022};
5023
5024static int btf_func_proto_check(struct btf_verifier_env *env,
5025 const struct btf_type *t)
5026{
5027 const struct btf_type *ret_type;
5028 const struct btf_param *args;
5029 const struct btf *btf;
5030 u16 nr_args, i;
5031 int err;
5032
5033 btf = env->btf;
5034 args = (const struct btf_param *)(t + 1);
5035 nr_args = btf_type_vlen(t);
5036
5037 /* Check func return type which could be "void" (t->type == 0) */
5038 if (t->type) {
5039 u32 ret_type_id = t->type;
5040
5041 ret_type = btf_type_by_id(btf, ret_type_id);
5042 if (!ret_type) {
5043 btf_verifier_log_type(env, t, "Invalid return type");
5044 return -EINVAL;
5045 }
5046
5047 if (btf_type_is_resolve_source_only(ret_type)) {
5048 btf_verifier_log_type(env, t, "Invalid return type");
5049 return -EINVAL;
5050 }
5051
5052 if (btf_type_needs_resolve(ret_type) &&
5053 !env_type_is_resolved(env, ret_type_id)) {
5054 err = btf_resolve(env, ret_type, ret_type_id);
5055 if (err)
5056 return err;
5057 }
5058
5059 /* Ensure the return type is a type that has a size */
5060 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
5061 btf_verifier_log_type(env, t, "Invalid return type");
5062 return -EINVAL;
5063 }
5064 }
5065
5066 if (!nr_args)
5067 return 0;
5068
5069 /* Last func arg type_id could be 0 if it is a vararg */
5070 if (!args[nr_args - 1].type) {
5071 if (args[nr_args - 1].name_off) {
5072 btf_verifier_log_type(env, t, "Invalid arg#%u",
5073 nr_args);
5074 return -EINVAL;
5075 }
5076 nr_args--;
5077 }
5078
5079 for (i = 0; i < nr_args; i++) {
5080 const struct btf_type *arg_type;
5081 u32 arg_type_id;
5082
5083 arg_type_id = args[i].type;
5084 arg_type = btf_type_by_id(btf, arg_type_id);
5085 if (!arg_type) {
5086 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5087 return -EINVAL;
5088 }
5089
5090 if (btf_type_is_resolve_source_only(arg_type)) {
5091 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5092 return -EINVAL;
5093 }
5094
5095 if (args[i].name_off &&
5096 (!btf_name_offset_valid(btf, args[i].name_off) ||
5097 !btf_name_valid_identifier(btf, args[i].name_off))) {
5098 btf_verifier_log_type(env, t,
5099 "Invalid arg#%u", i + 1);
5100 return -EINVAL;
5101 }
5102
5103 if (btf_type_needs_resolve(arg_type) &&
5104 !env_type_is_resolved(env, arg_type_id)) {
5105 err = btf_resolve(env, arg_type, arg_type_id);
5106 if (err)
5107 return err;
5108 }
5109
5110 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
5111 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5112 return -EINVAL;
5113 }
5114 }
5115
5116 return 0;
5117}
5118
5119static int btf_func_check(struct btf_verifier_env *env,
5120 const struct btf_type *t)
5121{
5122 const struct btf_type *proto_type;
5123 const struct btf_param *args;
5124 const struct btf *btf;
5125 u16 nr_args, i;
5126
5127 btf = env->btf;
5128 proto_type = btf_type_by_id(btf, t->type);
5129
5130 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
5131 btf_verifier_log_type(env, t, "Invalid type_id");
5132 return -EINVAL;
5133 }
5134
5135 args = (const struct btf_param *)(proto_type + 1);
5136 nr_args = btf_type_vlen(proto_type);
5137 for (i = 0; i < nr_args; i++) {
5138 if (!args[i].name_off && args[i].type) {
5139 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5140 return -EINVAL;
5141 }
5142 }
5143
5144 return 0;
5145}
5146
5147static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
5148 [BTF_KIND_INT] = &int_ops,
5149 [BTF_KIND_PTR] = &ptr_ops,
5150 [BTF_KIND_ARRAY] = &array_ops,
5151 [BTF_KIND_STRUCT] = &struct_ops,
5152 [BTF_KIND_UNION] = &struct_ops,
5153 [BTF_KIND_ENUM] = &enum_ops,
5154 [BTF_KIND_FWD] = &fwd_ops,
5155 [BTF_KIND_TYPEDEF] = &modifier_ops,
5156 [BTF_KIND_VOLATILE] = &modifier_ops,
5157 [BTF_KIND_CONST] = &modifier_ops,
5158 [BTF_KIND_RESTRICT] = &modifier_ops,
5159 [BTF_KIND_FUNC] = &func_ops,
5160 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
5161 [BTF_KIND_VAR] = &var_ops,
5162 [BTF_KIND_DATASEC] = &datasec_ops,
5163 [BTF_KIND_FLOAT] = &float_ops,
5164 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
5165 [BTF_KIND_TYPE_TAG] = &modifier_ops,
5166 [BTF_KIND_ENUM64] = &enum64_ops,
5167};
5168
5169static s32 btf_check_meta(struct btf_verifier_env *env,
5170 const struct btf_type *t,
5171 u32 meta_left)
5172{
5173 u32 saved_meta_left = meta_left;
5174 s32 var_meta_size;
5175
5176 if (meta_left < sizeof(*t)) {
5177 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
5178 env->log_type_id, meta_left, sizeof(*t));
5179 return -EINVAL;
5180 }
5181 meta_left -= sizeof(*t);
5182
5183 if (t->info & ~BTF_INFO_MASK) {
5184 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
5185 env->log_type_id, t->info);
5186 return -EINVAL;
5187 }
5188
5189 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
5190 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
5191 btf_verifier_log(env, "[%u] Invalid kind:%u",
5192 env->log_type_id, BTF_INFO_KIND(t->info));
5193 return -EINVAL;
5194 }
5195
5196 if (!btf_name_offset_valid(env->btf, t->name_off)) {
5197 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
5198 env->log_type_id, t->name_off);
5199 return -EINVAL;
5200 }
5201
5202 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
5203 if (var_meta_size < 0)
5204 return var_meta_size;
5205
5206 meta_left -= var_meta_size;
5207
5208 return saved_meta_left - meta_left;
5209}
5210
5211static int btf_check_all_metas(struct btf_verifier_env *env)
5212{
5213 struct btf *btf = env->btf;
5214 struct btf_header *hdr;
5215 void *cur, *end;
5216
5217 hdr = &btf->hdr;
5218 cur = btf->nohdr_data + hdr->type_off;
5219 end = cur + hdr->type_len;
5220
5221 env->log_type_id = btf->base_btf ? btf->start_id : 1;
5222 while (cur < end) {
5223 struct btf_type *t = cur;
5224 s32 meta_size;
5225
5226 meta_size = btf_check_meta(env, t, end - cur);
5227 if (meta_size < 0)
5228 return meta_size;
5229
5230 btf_add_type(env, t);
5231 cur += meta_size;
5232 env->log_type_id++;
5233 }
5234
5235 return 0;
5236}
5237
5238static bool btf_resolve_valid(struct btf_verifier_env *env,
5239 const struct btf_type *t,
5240 u32 type_id)
5241{
5242 struct btf *btf = env->btf;
5243
5244 if (!env_type_is_resolved(env, type_id))
5245 return false;
5246
5247 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5248 return !btf_resolved_type_id(btf, type_id) &&
5249 !btf_resolved_type_size(btf, type_id);
5250
5251 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5252 return btf_resolved_type_id(btf, type_id) &&
5253 !btf_resolved_type_size(btf, type_id);
5254
5255 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5256 btf_type_is_var(t)) {
5257 t = btf_type_id_resolve(btf, &type_id);
5258 return t &&
5259 !btf_type_is_modifier(t) &&
5260 !btf_type_is_var(t) &&
5261 !btf_type_is_datasec(t);
5262 }
5263
5264 if (btf_type_is_array(t)) {
5265 const struct btf_array *array = btf_type_array(t);
5266 const struct btf_type *elem_type;
5267 u32 elem_type_id = array->type;
5268 u32 elem_size;
5269
5270 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5271 return elem_type && !btf_type_is_modifier(elem_type) &&
5272 (array->nelems * elem_size ==
5273 btf_resolved_type_size(btf, type_id));
5274 }
5275
5276 return false;
5277}
5278
5279static int btf_resolve(struct btf_verifier_env *env,
5280 const struct btf_type *t, u32 type_id)
5281{
5282 u32 save_log_type_id = env->log_type_id;
5283 const struct resolve_vertex *v;
5284 int err = 0;
5285
5286 env->resolve_mode = RESOLVE_TBD;
5287 env_stack_push(env, t, type_id);
5288 while (!err && (v = env_stack_peak(env))) {
5289 env->log_type_id = v->type_id;
5290 err = btf_type_ops(v->t)->resolve(env, v);
5291 }
5292
5293 env->log_type_id = type_id;
5294 if (err == -E2BIG) {
5295 btf_verifier_log_type(env, t,
5296 "Exceeded max resolving depth:%u",
5297 MAX_RESOLVE_DEPTH);
5298 } else if (err == -EEXIST) {
5299 btf_verifier_log_type(env, t, "Loop detected");
5300 }
5301
5302 /* Final sanity check */
5303 if (!err && !btf_resolve_valid(env, t, type_id)) {
5304 btf_verifier_log_type(env, t, "Invalid resolve state");
5305 err = -EINVAL;
5306 }
5307
5308 env->log_type_id = save_log_type_id;
5309 return err;
5310}
5311
5312static int btf_check_all_types(struct btf_verifier_env *env)
5313{
5314 struct btf *btf = env->btf;
5315 const struct btf_type *t;
5316 u32 type_id, i;
5317 int err;
5318
5319 err = env_resolve_init(env);
5320 if (err)
5321 return err;
5322
5323 env->phase++;
5324 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5325 type_id = btf->start_id + i;
5326 t = btf_type_by_id(btf, type_id);
5327
5328 env->log_type_id = type_id;
5329 if (btf_type_needs_resolve(t) &&
5330 !env_type_is_resolved(env, type_id)) {
5331 err = btf_resolve(env, t, type_id);
5332 if (err)
5333 return err;
5334 }
5335
5336 if (btf_type_is_func_proto(t)) {
5337 err = btf_func_proto_check(env, t);
5338 if (err)
5339 return err;
5340 }
5341 }
5342
5343 return 0;
5344}
5345
5346static int btf_parse_type_sec(struct btf_verifier_env *env)
5347{
5348 const struct btf_header *hdr = &env->btf->hdr;
5349 int err;
5350
5351 /* Type section must align to 4 bytes */
5352 if (hdr->type_off & (sizeof(u32) - 1)) {
5353 btf_verifier_log(env, "Unaligned type_off");
5354 return -EINVAL;
5355 }
5356
5357 if (!env->btf->base_btf && !hdr->type_len) {
5358 btf_verifier_log(env, "No type found");
5359 return -EINVAL;
5360 }
5361
5362 err = btf_check_all_metas(env);
5363 if (err)
5364 return err;
5365
5366 return btf_check_all_types(env);
5367}
5368
5369static int btf_parse_str_sec(struct btf_verifier_env *env)
5370{
5371 const struct btf_header *hdr;
5372 struct btf *btf = env->btf;
5373 const char *start, *end;
5374
5375 hdr = &btf->hdr;
5376 start = btf->nohdr_data + hdr->str_off;
5377 end = start + hdr->str_len;
5378
5379 if (end != btf->data + btf->data_size) {
5380 btf_verifier_log(env, "String section is not at the end");
5381 return -EINVAL;
5382 }
5383
5384 btf->strings = start;
5385
5386 if (btf->base_btf && !hdr->str_len)
5387 return 0;
5388 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5389 btf_verifier_log(env, "Invalid string section");
5390 return -EINVAL;
5391 }
5392 if (!btf->base_btf && start[0]) {
5393 btf_verifier_log(env, "Invalid string section");
5394 return -EINVAL;
5395 }
5396
5397 return 0;
5398}
5399
5400static const size_t btf_sec_info_offset[] = {
5401 offsetof(struct btf_header, type_off),
5402 offsetof(struct btf_header, str_off),
5403};
5404
5405static int btf_sec_info_cmp(const void *a, const void *b)
5406{
5407 const struct btf_sec_info *x = a;
5408 const struct btf_sec_info *y = b;
5409
5410 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5411}
5412
5413static int btf_check_sec_info(struct btf_verifier_env *env,
5414 u32 btf_data_size)
5415{
5416 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5417 u32 total, expected_total, i;
5418 const struct btf_header *hdr;
5419 const struct btf *btf;
5420
5421 btf = env->btf;
5422 hdr = &btf->hdr;
5423
5424 /* Populate the secs from hdr */
5425 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5426 secs[i] = *(struct btf_sec_info *)((void *)hdr +
5427 btf_sec_info_offset[i]);
5428
5429 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5430 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5431
5432 /* Check for gaps and overlap among sections */
5433 total = 0;
5434 expected_total = btf_data_size - hdr->hdr_len;
5435 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5436 if (expected_total < secs[i].off) {
5437 btf_verifier_log(env, "Invalid section offset");
5438 return -EINVAL;
5439 }
5440 if (total < secs[i].off) {
5441 /* gap */
5442 btf_verifier_log(env, "Unsupported section found");
5443 return -EINVAL;
5444 }
5445 if (total > secs[i].off) {
5446 btf_verifier_log(env, "Section overlap found");
5447 return -EINVAL;
5448 }
5449 if (expected_total - total < secs[i].len) {
5450 btf_verifier_log(env,
5451 "Total section length too long");
5452 return -EINVAL;
5453 }
5454 total += secs[i].len;
5455 }
5456
5457 /* There is data other than hdr and known sections */
5458 if (expected_total != total) {
5459 btf_verifier_log(env, "Unsupported section found");
5460 return -EINVAL;
5461 }
5462
5463 return 0;
5464}
5465
5466static int btf_parse_hdr(struct btf_verifier_env *env)
5467{
5468 u32 hdr_len, hdr_copy, btf_data_size;
5469 const struct btf_header *hdr;
5470 struct btf *btf;
5471
5472 btf = env->btf;
5473 btf_data_size = btf->data_size;
5474
5475 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5476 btf_verifier_log(env, "hdr_len not found");
5477 return -EINVAL;
5478 }
5479
5480 hdr = btf->data;
5481 hdr_len = hdr->hdr_len;
5482 if (btf_data_size < hdr_len) {
5483 btf_verifier_log(env, "btf_header not found");
5484 return -EINVAL;
5485 }
5486
5487 /* Ensure the unsupported header fields are zero */
5488 if (hdr_len > sizeof(btf->hdr)) {
5489 u8 *expected_zero = btf->data + sizeof(btf->hdr);
5490 u8 *end = btf->data + hdr_len;
5491
5492 for (; expected_zero < end; expected_zero++) {
5493 if (*expected_zero) {
5494 btf_verifier_log(env, "Unsupported btf_header");
5495 return -E2BIG;
5496 }
5497 }
5498 }
5499
5500 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5501 memcpy(&btf->hdr, btf->data, hdr_copy);
5502
5503 hdr = &btf->hdr;
5504
5505 btf_verifier_log_hdr(env, btf_data_size);
5506
5507 if (hdr->magic != BTF_MAGIC) {
5508 btf_verifier_log(env, "Invalid magic");
5509 return -EINVAL;
5510 }
5511
5512 if (hdr->version != BTF_VERSION) {
5513 btf_verifier_log(env, "Unsupported version");
5514 return -ENOTSUPP;
5515 }
5516
5517 if (hdr->flags) {
5518 btf_verifier_log(env, "Unsupported flags");
5519 return -ENOTSUPP;
5520 }
5521
5522 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5523 btf_verifier_log(env, "No data");
5524 return -EINVAL;
5525 }
5526
5527 return btf_check_sec_info(env, btf_data_size);
5528}
5529
5530static const char *alloc_obj_fields[] = {
5531 "bpf_spin_lock",
5532 "bpf_list_head",
5533 "bpf_list_node",
5534 "bpf_rb_root",
5535 "bpf_rb_node",
5536 "bpf_refcount",
5537};
5538
5539static struct btf_struct_metas *
5540btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5541{
5542 struct btf_struct_metas *tab = NULL;
5543 struct btf_id_set *aof;
5544 int i, n, id, ret;
5545
5546 BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5547 BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5548
5549 aof = kmalloc(sizeof(*aof), GFP_KERNEL | __GFP_NOWARN);
5550 if (!aof)
5551 return ERR_PTR(-ENOMEM);
5552 aof->cnt = 0;
5553
5554 for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5555 /* Try to find whether this special type exists in user BTF, and
5556 * if so remember its ID so we can easily find it among members
5557 * of structs that we iterate in the next loop.
5558 */
5559 struct btf_id_set *new_aof;
5560
5561 id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5562 if (id < 0)
5563 continue;
5564
5565 new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),
5566 GFP_KERNEL | __GFP_NOWARN);
5567 if (!new_aof) {
5568 ret = -ENOMEM;
5569 goto free_aof;
5570 }
5571 aof = new_aof;
5572 aof->ids[aof->cnt++] = id;
5573 }
5574
5575 n = btf_nr_types(btf);
5576 for (i = 1; i < n; i++) {
5577 /* Try to find if there are kptrs in user BTF and remember their ID */
5578 struct btf_id_set *new_aof;
5579 struct btf_field_info tmp;
5580 const struct btf_type *t;
5581
5582 t = btf_type_by_id(btf, i);
5583 if (!t) {
5584 ret = -EINVAL;
5585 goto free_aof;
5586 }
5587
5588 ret = btf_find_kptr(btf, t, 0, 0, &tmp, BPF_KPTR);
5589 if (ret != BTF_FIELD_FOUND)
5590 continue;
5591
5592 new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),
5593 GFP_KERNEL | __GFP_NOWARN);
5594 if (!new_aof) {
5595 ret = -ENOMEM;
5596 goto free_aof;
5597 }
5598 aof = new_aof;
5599 aof->ids[aof->cnt++] = i;
5600 }
5601
5602 if (!aof->cnt) {
5603 kfree(aof);
5604 return NULL;
5605 }
5606 sort(&aof->ids, aof->cnt, sizeof(aof->ids[0]), btf_id_cmp_func, NULL);
5607
5608 for (i = 1; i < n; i++) {
5609 struct btf_struct_metas *new_tab;
5610 const struct btf_member *member;
5611 struct btf_struct_meta *type;
5612 struct btf_record *record;
5613 const struct btf_type *t;
5614 int j, tab_cnt;
5615
5616 t = btf_type_by_id(btf, i);
5617 if (!__btf_type_is_struct(t))
5618 continue;
5619
5620 cond_resched();
5621
5622 for_each_member(j, t, member) {
5623 if (btf_id_set_contains(aof, member->type))
5624 goto parse;
5625 }
5626 continue;
5627 parse:
5628 tab_cnt = tab ? tab->cnt : 0;
5629 new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5630 GFP_KERNEL | __GFP_NOWARN);
5631 if (!new_tab) {
5632 ret = -ENOMEM;
5633 goto free;
5634 }
5635 if (!tab)
5636 new_tab->cnt = 0;
5637 tab = new_tab;
5638
5639 type = &tab->types[tab->cnt];
5640 type->btf_id = i;
5641 record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5642 BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT |
5643 BPF_KPTR, t->size);
5644 /* The record cannot be unset, treat it as an error if so */
5645 if (IS_ERR_OR_NULL(record)) {
5646 ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5647 goto free;
5648 }
5649 type->record = record;
5650 tab->cnt++;
5651 }
5652 kfree(aof);
5653 return tab;
5654free:
5655 btf_struct_metas_free(tab);
5656free_aof:
5657 kfree(aof);
5658 return ERR_PTR(ret);
5659}
5660
5661struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5662{
5663 struct btf_struct_metas *tab;
5664
5665 BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5666 tab = btf->struct_meta_tab;
5667 if (!tab)
5668 return NULL;
5669 return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5670}
5671
5672static int btf_check_type_tags(struct btf_verifier_env *env,
5673 struct btf *btf, int start_id)
5674{
5675 int i, n, good_id = start_id - 1;
5676 bool in_tags;
5677
5678 n = btf_nr_types(btf);
5679 for (i = start_id; i < n; i++) {
5680 const struct btf_type *t;
5681 int chain_limit = 32;
5682 u32 cur_id = i;
5683
5684 t = btf_type_by_id(btf, i);
5685 if (!t)
5686 return -EINVAL;
5687 if (!btf_type_is_modifier(t))
5688 continue;
5689
5690 cond_resched();
5691
5692 in_tags = btf_type_is_type_tag(t);
5693 while (btf_type_is_modifier(t)) {
5694 if (!chain_limit--) {
5695 btf_verifier_log(env, "Max chain length or cycle detected");
5696 return -ELOOP;
5697 }
5698 if (btf_type_is_type_tag(t)) {
5699 if (!in_tags) {
5700 btf_verifier_log(env, "Type tags don't precede modifiers");
5701 return -EINVAL;
5702 }
5703 } else if (in_tags) {
5704 in_tags = false;
5705 }
5706 if (cur_id <= good_id)
5707 break;
5708 /* Move to next type */
5709 cur_id = t->type;
5710 t = btf_type_by_id(btf, cur_id);
5711 if (!t)
5712 return -EINVAL;
5713 }
5714 good_id = i;
5715 }
5716 return 0;
5717}
5718
5719static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5720{
5721 u32 log_true_size;
5722 int err;
5723
5724 err = bpf_vlog_finalize(log, &log_true_size);
5725
5726 if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5727 copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5728 &log_true_size, sizeof(log_true_size)))
5729 err = -EFAULT;
5730
5731 return err;
5732}
5733
5734static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5735{
5736 bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5737 char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5738 struct btf_struct_metas *struct_meta_tab;
5739 struct btf_verifier_env *env = NULL;
5740 struct btf *btf = NULL;
5741 u8 *data;
5742 int err, ret;
5743
5744 if (attr->btf_size > BTF_MAX_SIZE)
5745 return ERR_PTR(-E2BIG);
5746
5747 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5748 if (!env)
5749 return ERR_PTR(-ENOMEM);
5750
5751 /* user could have requested verbose verifier output
5752 * and supplied buffer to store the verification trace
5753 */
5754 err = bpf_vlog_init(&env->log, attr->btf_log_level,
5755 log_ubuf, attr->btf_log_size);
5756 if (err)
5757 goto errout_free;
5758
5759 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5760 if (!btf) {
5761 err = -ENOMEM;
5762 goto errout;
5763 }
5764 env->btf = btf;
5765
5766 data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5767 if (!data) {
5768 err = -ENOMEM;
5769 goto errout;
5770 }
5771
5772 btf->data = data;
5773 btf->data_size = attr->btf_size;
5774
5775 if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5776 err = -EFAULT;
5777 goto errout;
5778 }
5779
5780 err = btf_parse_hdr(env);
5781 if (err)
5782 goto errout;
5783
5784 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5785
5786 err = btf_parse_str_sec(env);
5787 if (err)
5788 goto errout;
5789
5790 err = btf_parse_type_sec(env);
5791 if (err)
5792 goto errout;
5793
5794 err = btf_check_type_tags(env, btf, 1);
5795 if (err)
5796 goto errout;
5797
5798 struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5799 if (IS_ERR(struct_meta_tab)) {
5800 err = PTR_ERR(struct_meta_tab);
5801 goto errout;
5802 }
5803 btf->struct_meta_tab = struct_meta_tab;
5804
5805 if (struct_meta_tab) {
5806 int i;
5807
5808 for (i = 0; i < struct_meta_tab->cnt; i++) {
5809 err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5810 if (err < 0)
5811 goto errout_meta;
5812 }
5813 }
5814
5815 err = finalize_log(&env->log, uattr, uattr_size);
5816 if (err)
5817 goto errout_free;
5818
5819 btf_verifier_env_free(env);
5820 refcount_set(&btf->refcnt, 1);
5821 return btf;
5822
5823errout_meta:
5824 btf_free_struct_meta_tab(btf);
5825errout:
5826 /* overwrite err with -ENOSPC or -EFAULT */
5827 ret = finalize_log(&env->log, uattr, uattr_size);
5828 if (ret)
5829 err = ret;
5830errout_free:
5831 btf_verifier_env_free(env);
5832 if (btf)
5833 btf_free(btf);
5834 return ERR_PTR(err);
5835}
5836
5837extern char __start_BTF[];
5838extern char __stop_BTF[];
5839extern struct btf *btf_vmlinux;
5840
5841#define BPF_MAP_TYPE(_id, _ops)
5842#define BPF_LINK_TYPE(_id, _name)
5843static union {
5844 struct bpf_ctx_convert {
5845#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5846 prog_ctx_type _id##_prog; \
5847 kern_ctx_type _id##_kern;
5848#include <linux/bpf_types.h>
5849#undef BPF_PROG_TYPE
5850 } *__t;
5851 /* 't' is written once under lock. Read many times. */
5852 const struct btf_type *t;
5853} bpf_ctx_convert;
5854enum {
5855#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5856 __ctx_convert##_id,
5857#include <linux/bpf_types.h>
5858#undef BPF_PROG_TYPE
5859 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5860};
5861static u8 bpf_ctx_convert_map[] = {
5862#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5863 [_id] = __ctx_convert##_id,
5864#include <linux/bpf_types.h>
5865#undef BPF_PROG_TYPE
5866 0, /* avoid empty array */
5867};
5868#undef BPF_MAP_TYPE
5869#undef BPF_LINK_TYPE
5870
5871static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5872{
5873 const struct btf_type *conv_struct;
5874 const struct btf_member *ctx_type;
5875
5876 conv_struct = bpf_ctx_convert.t;
5877 if (!conv_struct)
5878 return NULL;
5879 /* prog_type is valid bpf program type. No need for bounds check. */
5880 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5881 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5882 * Like 'struct __sk_buff'
5883 */
5884 return btf_type_by_id(btf_vmlinux, ctx_type->type);
5885}
5886
5887static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5888{
5889 const struct btf_type *conv_struct;
5890 const struct btf_member *ctx_type;
5891
5892 conv_struct = bpf_ctx_convert.t;
5893 if (!conv_struct)
5894 return -EFAULT;
5895 /* prog_type is valid bpf program type. No need for bounds check. */
5896 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5897 /* ctx_type is a pointer to prog_ctx_type in vmlinux.
5898 * Like 'struct sk_buff'
5899 */
5900 return ctx_type->type;
5901}
5902
5903bool btf_is_projection_of(const char *pname, const char *tname)
5904{
5905 if (strcmp(pname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5906 return true;
5907 if (strcmp(pname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5908 return true;
5909 return false;
5910}
5911
5912bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5913 const struct btf_type *t, enum bpf_prog_type prog_type,
5914 int arg)
5915{
5916 const struct btf_type *ctx_type;
5917 const char *tname, *ctx_tname;
5918
5919 t = btf_type_by_id(btf, t->type);
5920
5921 /* KPROBE programs allow bpf_user_pt_regs_t typedef, which we need to
5922 * check before we skip all the typedef below.
5923 */
5924 if (prog_type == BPF_PROG_TYPE_KPROBE) {
5925 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5926 t = btf_type_by_id(btf, t->type);
5927
5928 if (btf_type_is_typedef(t)) {
5929 tname = btf_name_by_offset(btf, t->name_off);
5930 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5931 return true;
5932 }
5933 }
5934
5935 while (btf_type_is_modifier(t))
5936 t = btf_type_by_id(btf, t->type);
5937 if (!btf_type_is_struct(t)) {
5938 /* Only pointer to struct is supported for now.
5939 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5940 * is not supported yet.
5941 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5942 */
5943 return false;
5944 }
5945 tname = btf_name_by_offset(btf, t->name_off);
5946 if (!tname) {
5947 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5948 return false;
5949 }
5950
5951 ctx_type = find_canonical_prog_ctx_type(prog_type);
5952 if (!ctx_type) {
5953 bpf_log(log, "btf_vmlinux is malformed\n");
5954 /* should not happen */
5955 return false;
5956 }
5957again:
5958 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5959 if (!ctx_tname) {
5960 /* should not happen */
5961 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5962 return false;
5963 }
5964 /* program types without named context types work only with arg:ctx tag */
5965 if (ctx_tname[0] == '\0')
5966 return false;
5967 /* only compare that prog's ctx type name is the same as
5968 * kernel expects. No need to compare field by field.
5969 * It's ok for bpf prog to do:
5970 * struct __sk_buff {};
5971 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5972 * { // no fields of skb are ever used }
5973 */
5974 if (btf_is_projection_of(ctx_tname, tname))
5975 return true;
5976 if (strcmp(ctx_tname, tname)) {
5977 /* bpf_user_pt_regs_t is a typedef, so resolve it to
5978 * underlying struct and check name again
5979 */
5980 if (!btf_type_is_modifier(ctx_type))
5981 return false;
5982 while (btf_type_is_modifier(ctx_type))
5983 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5984 goto again;
5985 }
5986 return true;
5987}
5988
5989/* forward declarations for arch-specific underlying types of
5990 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
5991 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
5992 * works correctly with __builtin_types_compatible_p() on respective
5993 * architectures
5994 */
5995struct user_regs_struct;
5996struct user_pt_regs;
5997
5998static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5999 const struct btf_type *t, int arg,
6000 enum bpf_prog_type prog_type,
6001 enum bpf_attach_type attach_type)
6002{
6003 const struct btf_type *ctx_type;
6004 const char *tname, *ctx_tname;
6005
6006 if (!btf_is_ptr(t)) {
6007 bpf_log(log, "arg#%d type isn't a pointer\n", arg);
6008 return -EINVAL;
6009 }
6010 t = btf_type_by_id(btf, t->type);
6011
6012 /* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
6013 if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
6014 while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
6015 t = btf_type_by_id(btf, t->type);
6016
6017 if (btf_type_is_typedef(t)) {
6018 tname = btf_name_by_offset(btf, t->name_off);
6019 if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
6020 return 0;
6021 }
6022 }
6023
6024 /* all other program types don't use typedefs for context type */
6025 while (btf_type_is_modifier(t))
6026 t = btf_type_by_id(btf, t->type);
6027
6028 /* `void *ctx __arg_ctx` is always valid */
6029 if (btf_type_is_void(t))
6030 return 0;
6031
6032 tname = btf_name_by_offset(btf, t->name_off);
6033 if (str_is_empty(tname)) {
6034 bpf_log(log, "arg#%d type doesn't have a name\n", arg);
6035 return -EINVAL;
6036 }
6037
6038 /* special cases */
6039 switch (prog_type) {
6040 case BPF_PROG_TYPE_KPROBE:
6041 if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6042 return 0;
6043 break;
6044 case BPF_PROG_TYPE_PERF_EVENT:
6045 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
6046 __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6047 return 0;
6048 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
6049 __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
6050 return 0;
6051 if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
6052 __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
6053 return 0;
6054 break;
6055 case BPF_PROG_TYPE_RAW_TRACEPOINT:
6056 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
6057 /* allow u64* as ctx */
6058 if (btf_is_int(t) && t->size == 8)
6059 return 0;
6060 break;
6061 case BPF_PROG_TYPE_TRACING:
6062 switch (attach_type) {
6063 case BPF_TRACE_RAW_TP:
6064 /* tp_btf program is TRACING, so need special case here */
6065 if (__btf_type_is_struct(t) &&
6066 strcmp(tname, "bpf_raw_tracepoint_args") == 0)
6067 return 0;
6068 /* allow u64* as ctx */
6069 if (btf_is_int(t) && t->size == 8)
6070 return 0;
6071 break;
6072 case BPF_TRACE_ITER:
6073 /* allow struct bpf_iter__xxx types only */
6074 if (__btf_type_is_struct(t) &&
6075 strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
6076 return 0;
6077 break;
6078 case BPF_TRACE_FENTRY:
6079 case BPF_TRACE_FEXIT:
6080 case BPF_MODIFY_RETURN:
6081 /* allow u64* as ctx */
6082 if (btf_is_int(t) && t->size == 8)
6083 return 0;
6084 break;
6085 default:
6086 break;
6087 }
6088 break;
6089 case BPF_PROG_TYPE_LSM:
6090 case BPF_PROG_TYPE_STRUCT_OPS:
6091 /* allow u64* as ctx */
6092 if (btf_is_int(t) && t->size == 8)
6093 return 0;
6094 break;
6095 case BPF_PROG_TYPE_TRACEPOINT:
6096 case BPF_PROG_TYPE_SYSCALL:
6097 case BPF_PROG_TYPE_EXT:
6098 return 0; /* anything goes */
6099 default:
6100 break;
6101 }
6102
6103 ctx_type = find_canonical_prog_ctx_type(prog_type);
6104 if (!ctx_type) {
6105 /* should not happen */
6106 bpf_log(log, "btf_vmlinux is malformed\n");
6107 return -EINVAL;
6108 }
6109
6110 /* resolve typedefs and check that underlying structs are matching as well */
6111 while (btf_type_is_modifier(ctx_type))
6112 ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
6113
6114 /* if program type doesn't have distinctly named struct type for
6115 * context, then __arg_ctx argument can only be `void *`, which we
6116 * already checked above
6117 */
6118 if (!__btf_type_is_struct(ctx_type)) {
6119 bpf_log(log, "arg#%d should be void pointer\n", arg);
6120 return -EINVAL;
6121 }
6122
6123 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
6124 if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
6125 bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
6126 return -EINVAL;
6127 }
6128
6129 return 0;
6130}
6131
6132static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
6133 struct btf *btf,
6134 const struct btf_type *t,
6135 enum bpf_prog_type prog_type,
6136 int arg)
6137{
6138 if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg))
6139 return -ENOENT;
6140 return find_kern_ctx_type_id(prog_type);
6141}
6142
6143int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
6144{
6145 const struct btf_member *kctx_member;
6146 const struct btf_type *conv_struct;
6147 const struct btf_type *kctx_type;
6148 u32 kctx_type_id;
6149
6150 conv_struct = bpf_ctx_convert.t;
6151 /* get member for kernel ctx type */
6152 kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
6153 kctx_type_id = kctx_member->type;
6154 kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
6155 if (!btf_type_is_struct(kctx_type)) {
6156 bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
6157 return -EINVAL;
6158 }
6159
6160 return kctx_type_id;
6161}
6162
6163BTF_ID_LIST(bpf_ctx_convert_btf_id)
6164BTF_ID(struct, bpf_ctx_convert)
6165
6166static struct btf *btf_parse_base(struct btf_verifier_env *env, const char *name,
6167 void *data, unsigned int data_size)
6168{
6169 struct btf *btf = NULL;
6170 int err;
6171
6172 if (!IS_ENABLED(CONFIG_DEBUG_INFO_BTF))
6173 return ERR_PTR(-ENOENT);
6174
6175 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6176 if (!btf) {
6177 err = -ENOMEM;
6178 goto errout;
6179 }
6180 env->btf = btf;
6181
6182 btf->data = data;
6183 btf->data_size = data_size;
6184 btf->kernel_btf = true;
6185 snprintf(btf->name, sizeof(btf->name), "%s", name);
6186
6187 err = btf_parse_hdr(env);
6188 if (err)
6189 goto errout;
6190
6191 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6192
6193 err = btf_parse_str_sec(env);
6194 if (err)
6195 goto errout;
6196
6197 err = btf_check_all_metas(env);
6198 if (err)
6199 goto errout;
6200
6201 err = btf_check_type_tags(env, btf, 1);
6202 if (err)
6203 goto errout;
6204
6205 refcount_set(&btf->refcnt, 1);
6206
6207 return btf;
6208
6209errout:
6210 if (btf) {
6211 kvfree(btf->types);
6212 kfree(btf);
6213 }
6214 return ERR_PTR(err);
6215}
6216
6217struct btf *btf_parse_vmlinux(void)
6218{
6219 struct btf_verifier_env *env = NULL;
6220 struct bpf_verifier_log *log;
6221 struct btf *btf;
6222 int err;
6223
6224 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6225 if (!env)
6226 return ERR_PTR(-ENOMEM);
6227
6228 log = &env->log;
6229 log->level = BPF_LOG_KERNEL;
6230 btf = btf_parse_base(env, "vmlinux", __start_BTF, __stop_BTF - __start_BTF);
6231 if (IS_ERR(btf))
6232 goto err_out;
6233
6234 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
6235 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
6236 err = btf_alloc_id(btf);
6237 if (err) {
6238 btf_free(btf);
6239 btf = ERR_PTR(err);
6240 }
6241err_out:
6242 btf_verifier_env_free(env);
6243 return btf;
6244}
6245
6246/* If .BTF_ids section was created with distilled base BTF, both base and
6247 * split BTF ids will need to be mapped to actual base/split ids for
6248 * BTF now that it has been relocated.
6249 */
6250static __u32 btf_relocate_id(const struct btf *btf, __u32 id)
6251{
6252 if (!btf->base_btf || !btf->base_id_map)
6253 return id;
6254 return btf->base_id_map[id];
6255}
6256
6257#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6258
6259static struct btf *btf_parse_module(const char *module_name, const void *data,
6260 unsigned int data_size, void *base_data,
6261 unsigned int base_data_size)
6262{
6263 struct btf *btf = NULL, *vmlinux_btf, *base_btf = NULL;
6264 struct btf_verifier_env *env = NULL;
6265 struct bpf_verifier_log *log;
6266 int err = 0;
6267
6268 vmlinux_btf = bpf_get_btf_vmlinux();
6269 if (IS_ERR(vmlinux_btf))
6270 return vmlinux_btf;
6271 if (!vmlinux_btf)
6272 return ERR_PTR(-EINVAL);
6273
6274 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6275 if (!env)
6276 return ERR_PTR(-ENOMEM);
6277
6278 log = &env->log;
6279 log->level = BPF_LOG_KERNEL;
6280
6281 if (base_data) {
6282 base_btf = btf_parse_base(env, ".BTF.base", base_data, base_data_size);
6283 if (IS_ERR(base_btf)) {
6284 err = PTR_ERR(base_btf);
6285 goto errout;
6286 }
6287 } else {
6288 base_btf = vmlinux_btf;
6289 }
6290
6291 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6292 if (!btf) {
6293 err = -ENOMEM;
6294 goto errout;
6295 }
6296 env->btf = btf;
6297
6298 btf->base_btf = base_btf;
6299 btf->start_id = base_btf->nr_types;
6300 btf->start_str_off = base_btf->hdr.str_len;
6301 btf->kernel_btf = true;
6302 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
6303
6304 btf->data = kvmemdup(data, data_size, GFP_KERNEL | __GFP_NOWARN);
6305 if (!btf->data) {
6306 err = -ENOMEM;
6307 goto errout;
6308 }
6309 btf->data_size = data_size;
6310
6311 err = btf_parse_hdr(env);
6312 if (err)
6313 goto errout;
6314
6315 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6316
6317 err = btf_parse_str_sec(env);
6318 if (err)
6319 goto errout;
6320
6321 err = btf_check_all_metas(env);
6322 if (err)
6323 goto errout;
6324
6325 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6326 if (err)
6327 goto errout;
6328
6329 if (base_btf != vmlinux_btf) {
6330 err = btf_relocate(btf, vmlinux_btf, &btf->base_id_map);
6331 if (err)
6332 goto errout;
6333 btf_free(base_btf);
6334 base_btf = vmlinux_btf;
6335 }
6336
6337 btf_verifier_env_free(env);
6338 refcount_set(&btf->refcnt, 1);
6339 return btf;
6340
6341errout:
6342 btf_verifier_env_free(env);
6343 if (!IS_ERR(base_btf) && base_btf != vmlinux_btf)
6344 btf_free(base_btf);
6345 if (btf) {
6346 kvfree(btf->data);
6347 kvfree(btf->types);
6348 kfree(btf);
6349 }
6350 return ERR_PTR(err);
6351}
6352
6353#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6354
6355struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6356{
6357 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6358
6359 if (tgt_prog)
6360 return tgt_prog->aux->btf;
6361 else
6362 return prog->aux->attach_btf;
6363}
6364
6365static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
6366{
6367 /* skip modifiers */
6368 t = btf_type_skip_modifiers(btf, t->type, NULL);
6369
6370 return btf_type_is_int(t);
6371}
6372
6373static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6374 int off)
6375{
6376 const struct btf_param *args;
6377 const struct btf_type *t;
6378 u32 offset = 0, nr_args;
6379 int i;
6380
6381 if (!func_proto)
6382 return off / 8;
6383
6384 nr_args = btf_type_vlen(func_proto);
6385 args = (const struct btf_param *)(func_proto + 1);
6386 for (i = 0; i < nr_args; i++) {
6387 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6388 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6389 if (off < offset)
6390 return i;
6391 }
6392
6393 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6394 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6395 if (off < offset)
6396 return nr_args;
6397
6398 return nr_args + 1;
6399}
6400
6401static bool prog_args_trusted(const struct bpf_prog *prog)
6402{
6403 enum bpf_attach_type atype = prog->expected_attach_type;
6404
6405 switch (prog->type) {
6406 case BPF_PROG_TYPE_TRACING:
6407 return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6408 case BPF_PROG_TYPE_LSM:
6409 return bpf_lsm_is_trusted(prog);
6410 case BPF_PROG_TYPE_STRUCT_OPS:
6411 return true;
6412 default:
6413 return false;
6414 }
6415}
6416
6417int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto,
6418 u32 arg_no)
6419{
6420 const struct btf_param *args;
6421 const struct btf_type *t;
6422 int off = 0, i;
6423 u32 sz;
6424
6425 args = btf_params(func_proto);
6426 for (i = 0; i < arg_no; i++) {
6427 t = btf_type_by_id(btf, args[i].type);
6428 t = btf_resolve_size(btf, t, &sz);
6429 if (IS_ERR(t))
6430 return PTR_ERR(t);
6431 off += roundup(sz, 8);
6432 }
6433
6434 return off;
6435}
6436
6437struct bpf_raw_tp_null_args {
6438 const char *func;
6439 u64 mask;
6440};
6441
6442static const struct bpf_raw_tp_null_args raw_tp_null_args[] = {
6443 /* sched */
6444 { "sched_pi_setprio", 0x10 },
6445 /* ... from sched_numa_pair_template event class */
6446 { "sched_stick_numa", 0x100 },
6447 { "sched_swap_numa", 0x100 },
6448 /* afs */
6449 { "afs_make_fs_call", 0x10 },
6450 { "afs_make_fs_calli", 0x10 },
6451 { "afs_make_fs_call1", 0x10 },
6452 { "afs_make_fs_call2", 0x10 },
6453 { "afs_protocol_error", 0x1 },
6454 { "afs_flock_ev", 0x10 },
6455 /* cachefiles */
6456 { "cachefiles_lookup", 0x1 | 0x200 },
6457 { "cachefiles_unlink", 0x1 },
6458 { "cachefiles_rename", 0x1 },
6459 { "cachefiles_prep_read", 0x1 },
6460 { "cachefiles_mark_active", 0x1 },
6461 { "cachefiles_mark_failed", 0x1 },
6462 { "cachefiles_mark_inactive", 0x1 },
6463 { "cachefiles_vfs_error", 0x1 },
6464 { "cachefiles_io_error", 0x1 },
6465 { "cachefiles_ondemand_open", 0x1 },
6466 { "cachefiles_ondemand_copen", 0x1 },
6467 { "cachefiles_ondemand_close", 0x1 },
6468 { "cachefiles_ondemand_read", 0x1 },
6469 { "cachefiles_ondemand_cread", 0x1 },
6470 { "cachefiles_ondemand_fd_write", 0x1 },
6471 { "cachefiles_ondemand_fd_release", 0x1 },
6472 /* ext4, from ext4__mballoc event class */
6473 { "ext4_mballoc_discard", 0x10 },
6474 { "ext4_mballoc_free", 0x10 },
6475 /* fib */
6476 { "fib_table_lookup", 0x100 },
6477 /* filelock */
6478 /* ... from filelock_lock event class */
6479 { "posix_lock_inode", 0x10 },
6480 { "fcntl_setlk", 0x10 },
6481 { "locks_remove_posix", 0x10 },
6482 { "flock_lock_inode", 0x10 },
6483 /* ... from filelock_lease event class */
6484 { "break_lease_noblock", 0x10 },
6485 { "break_lease_block", 0x10 },
6486 { "break_lease_unblock", 0x10 },
6487 { "generic_delete_lease", 0x10 },
6488 { "time_out_leases", 0x10 },
6489 /* host1x */
6490 { "host1x_cdma_push_gather", 0x10000 },
6491 /* huge_memory */
6492 { "mm_khugepaged_scan_pmd", 0x10 },
6493 { "mm_collapse_huge_page_isolate", 0x1 },
6494 { "mm_khugepaged_scan_file", 0x10 },
6495 { "mm_khugepaged_collapse_file", 0x10 },
6496 /* kmem */
6497 { "mm_page_alloc", 0x1 },
6498 { "mm_page_pcpu_drain", 0x1 },
6499 /* .. from mm_page event class */
6500 { "mm_page_alloc_zone_locked", 0x1 },
6501 /* netfs */
6502 { "netfs_failure", 0x10 },
6503 /* power */
6504 { "device_pm_callback_start", 0x10 },
6505 /* qdisc */
6506 { "qdisc_dequeue", 0x1000 },
6507 /* rxrpc */
6508 { "rxrpc_recvdata", 0x1 },
6509 { "rxrpc_resend", 0x10 },
6510 /* skb */
6511 {"kfree_skb", 0x1000},
6512 /* sunrpc */
6513 { "xs_stream_read_data", 0x1 },
6514 /* ... from xprt_cong_event event class */
6515 { "xprt_reserve_cong", 0x10 },
6516 { "xprt_release_cong", 0x10 },
6517 { "xprt_get_cong", 0x10 },
6518 { "xprt_put_cong", 0x10 },
6519 /* tcp */
6520 { "tcp_send_reset", 0x11 },
6521 /* tegra_apb_dma */
6522 { "tegra_dma_tx_status", 0x100 },
6523 /* timer_migration */
6524 { "tmigr_update_events", 0x1 },
6525 /* writeback, from writeback_folio_template event class */
6526 { "writeback_dirty_folio", 0x10 },
6527 { "folio_wait_writeback", 0x10 },
6528 /* rdma */
6529 { "mr_integ_alloc", 0x2000 },
6530 /* bpf_testmod */
6531 { "bpf_testmod_test_read", 0x0 },
6532};
6533
6534bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6535 const struct bpf_prog *prog,
6536 struct bpf_insn_access_aux *info)
6537{
6538 const struct btf_type *t = prog->aux->attach_func_proto;
6539 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6540 struct btf *btf = bpf_prog_get_target_btf(prog);
6541 const char *tname = prog->aux->attach_func_name;
6542 struct bpf_verifier_log *log = info->log;
6543 const struct btf_param *args;
6544 bool ptr_err_raw_tp = false;
6545 const char *tag_value;
6546 u32 nr_args, arg;
6547 int i, ret;
6548
6549 if (off % 8) {
6550 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6551 tname, off);
6552 return false;
6553 }
6554 arg = get_ctx_arg_idx(btf, t, off);
6555 args = (const struct btf_param *)(t + 1);
6556 /* if (t == NULL) Fall back to default BPF prog with
6557 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6558 */
6559 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6560 if (prog->aux->attach_btf_trace) {
6561 /* skip first 'void *__data' argument in btf_trace_##name typedef */
6562 args++;
6563 nr_args--;
6564 }
6565
6566 if (arg > nr_args) {
6567 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6568 tname, arg + 1);
6569 return false;
6570 }
6571
6572 if (arg == nr_args) {
6573 switch (prog->expected_attach_type) {
6574 case BPF_LSM_MAC:
6575 /* mark we are accessing the return value */
6576 info->is_retval = true;
6577 fallthrough;
6578 case BPF_LSM_CGROUP:
6579 case BPF_TRACE_FEXIT:
6580 /* When LSM programs are attached to void LSM hooks
6581 * they use FEXIT trampolines and when attached to
6582 * int LSM hooks, they use MODIFY_RETURN trampolines.
6583 *
6584 * While the LSM programs are BPF_MODIFY_RETURN-like
6585 * the check:
6586 *
6587 * if (ret_type != 'int')
6588 * return -EINVAL;
6589 *
6590 * is _not_ done here. This is still safe as LSM hooks
6591 * have only void and int return types.
6592 */
6593 if (!t)
6594 return true;
6595 t = btf_type_by_id(btf, t->type);
6596 break;
6597 case BPF_MODIFY_RETURN:
6598 /* For now the BPF_MODIFY_RETURN can only be attached to
6599 * functions that return an int.
6600 */
6601 if (!t)
6602 return false;
6603
6604 t = btf_type_skip_modifiers(btf, t->type, NULL);
6605 if (!btf_type_is_small_int(t)) {
6606 bpf_log(log,
6607 "ret type %s not allowed for fmod_ret\n",
6608 btf_type_str(t));
6609 return false;
6610 }
6611 break;
6612 default:
6613 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6614 tname, arg + 1);
6615 return false;
6616 }
6617 } else {
6618 if (!t)
6619 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6620 return true;
6621 t = btf_type_by_id(btf, args[arg].type);
6622 }
6623
6624 /* skip modifiers */
6625 while (btf_type_is_modifier(t))
6626 t = btf_type_by_id(btf, t->type);
6627 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6628 /* accessing a scalar */
6629 return true;
6630 if (!btf_type_is_ptr(t)) {
6631 bpf_log(log,
6632 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6633 tname, arg,
6634 __btf_name_by_offset(btf, t->name_off),
6635 btf_type_str(t));
6636 return false;
6637 }
6638
6639 if (size != sizeof(u64)) {
6640 bpf_log(log, "func '%s' size %d must be 8\n",
6641 tname, size);
6642 return false;
6643 }
6644
6645 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6646 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6647 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6648 u32 type, flag;
6649
6650 type = base_type(ctx_arg_info->reg_type);
6651 flag = type_flag(ctx_arg_info->reg_type);
6652 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6653 (flag & PTR_MAYBE_NULL)) {
6654 info->reg_type = ctx_arg_info->reg_type;
6655 return true;
6656 }
6657 }
6658
6659 if (t->type == 0)
6660 /* This is a pointer to void.
6661 * It is the same as scalar from the verifier safety pov.
6662 * No further pointer walking is allowed.
6663 */
6664 return true;
6665
6666 if (is_int_ptr(btf, t))
6667 return true;
6668
6669 /* this is a pointer to another type */
6670 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6671 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6672
6673 if (ctx_arg_info->offset == off) {
6674 if (!ctx_arg_info->btf_id) {
6675 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6676 return false;
6677 }
6678
6679 info->reg_type = ctx_arg_info->reg_type;
6680 info->btf = ctx_arg_info->btf ? : btf_vmlinux;
6681 info->btf_id = ctx_arg_info->btf_id;
6682 return true;
6683 }
6684 }
6685
6686 info->reg_type = PTR_TO_BTF_ID;
6687 if (prog_args_trusted(prog))
6688 info->reg_type |= PTR_TRUSTED;
6689
6690 if (btf_param_match_suffix(btf, &args[arg], "__nullable"))
6691 info->reg_type |= PTR_MAYBE_NULL;
6692
6693 if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
6694 struct btf *btf = prog->aux->attach_btf;
6695 const struct btf_type *t;
6696 const char *tname;
6697
6698 /* BTF lookups cannot fail, return false on error */
6699 t = btf_type_by_id(btf, prog->aux->attach_btf_id);
6700 if (!t)
6701 return false;
6702 tname = btf_name_by_offset(btf, t->name_off);
6703 if (!tname)
6704 return false;
6705 /* Checked by bpf_check_attach_target */
6706 tname += sizeof("btf_trace_") - 1;
6707 for (i = 0; i < ARRAY_SIZE(raw_tp_null_args); i++) {
6708 /* Is this a func with potential NULL args? */
6709 if (strcmp(tname, raw_tp_null_args[i].func))
6710 continue;
6711 if (raw_tp_null_args[i].mask & (0x1 << (arg * 4)))
6712 info->reg_type |= PTR_MAYBE_NULL;
6713 /* Is the current arg IS_ERR? */
6714 if (raw_tp_null_args[i].mask & (0x2 << (arg * 4)))
6715 ptr_err_raw_tp = true;
6716 break;
6717 }
6718 /* If we don't know NULL-ness specification and the tracepoint
6719 * is coming from a loadable module, be conservative and mark
6720 * argument as PTR_MAYBE_NULL.
6721 */
6722 if (i == ARRAY_SIZE(raw_tp_null_args) && btf_is_module(btf))
6723 info->reg_type |= PTR_MAYBE_NULL;
6724 }
6725
6726 if (tgt_prog) {
6727 enum bpf_prog_type tgt_type;
6728
6729 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6730 tgt_type = tgt_prog->aux->saved_dst_prog_type;
6731 else
6732 tgt_type = tgt_prog->type;
6733
6734 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6735 if (ret > 0) {
6736 info->btf = btf_vmlinux;
6737 info->btf_id = ret;
6738 return true;
6739 } else {
6740 return false;
6741 }
6742 }
6743
6744 info->btf = btf;
6745 info->btf_id = t->type;
6746 t = btf_type_by_id(btf, t->type);
6747
6748 if (btf_type_is_type_tag(t)) {
6749 tag_value = __btf_name_by_offset(btf, t->name_off);
6750 if (strcmp(tag_value, "user") == 0)
6751 info->reg_type |= MEM_USER;
6752 if (strcmp(tag_value, "percpu") == 0)
6753 info->reg_type |= MEM_PERCPU;
6754 }
6755
6756 /* skip modifiers */
6757 while (btf_type_is_modifier(t)) {
6758 info->btf_id = t->type;
6759 t = btf_type_by_id(btf, t->type);
6760 }
6761 if (!btf_type_is_struct(t)) {
6762 bpf_log(log,
6763 "func '%s' arg%d type %s is not a struct\n",
6764 tname, arg, btf_type_str(t));
6765 return false;
6766 }
6767 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6768 tname, arg, info->btf_id, btf_type_str(t),
6769 __btf_name_by_offset(btf, t->name_off));
6770
6771 /* Perform all checks on the validity of type for this argument, but if
6772 * we know it can be IS_ERR at runtime, scrub pointer type and mark as
6773 * scalar.
6774 */
6775 if (ptr_err_raw_tp) {
6776 bpf_log(log, "marking pointer arg%d as scalar as it may encode error", arg);
6777 info->reg_type = SCALAR_VALUE;
6778 }
6779 return true;
6780}
6781EXPORT_SYMBOL_GPL(btf_ctx_access);
6782
6783enum bpf_struct_walk_result {
6784 /* < 0 error */
6785 WALK_SCALAR = 0,
6786 WALK_PTR,
6787 WALK_STRUCT,
6788};
6789
6790static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6791 const struct btf_type *t, int off, int size,
6792 u32 *next_btf_id, enum bpf_type_flag *flag,
6793 const char **field_name)
6794{
6795 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6796 const struct btf_type *mtype, *elem_type = NULL;
6797 const struct btf_member *member;
6798 const char *tname, *mname, *tag_value;
6799 u32 vlen, elem_id, mid;
6800
6801again:
6802 if (btf_type_is_modifier(t))
6803 t = btf_type_skip_modifiers(btf, t->type, NULL);
6804 tname = __btf_name_by_offset(btf, t->name_off);
6805 if (!btf_type_is_struct(t)) {
6806 bpf_log(log, "Type '%s' is not a struct\n", tname);
6807 return -EINVAL;
6808 }
6809
6810 vlen = btf_type_vlen(t);
6811 if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6812 /*
6813 * walking unions yields untrusted pointers
6814 * with exception of __bpf_md_ptr and other
6815 * unions with a single member
6816 */
6817 *flag |= PTR_UNTRUSTED;
6818
6819 if (off + size > t->size) {
6820 /* If the last element is a variable size array, we may
6821 * need to relax the rule.
6822 */
6823 struct btf_array *array_elem;
6824
6825 if (vlen == 0)
6826 goto error;
6827
6828 member = btf_type_member(t) + vlen - 1;
6829 mtype = btf_type_skip_modifiers(btf, member->type,
6830 NULL);
6831 if (!btf_type_is_array(mtype))
6832 goto error;
6833
6834 array_elem = (struct btf_array *)(mtype + 1);
6835 if (array_elem->nelems != 0)
6836 goto error;
6837
6838 moff = __btf_member_bit_offset(t, member) / 8;
6839 if (off < moff)
6840 goto error;
6841
6842 /* allow structure and integer */
6843 t = btf_type_skip_modifiers(btf, array_elem->type,
6844 NULL);
6845
6846 if (btf_type_is_int(t))
6847 return WALK_SCALAR;
6848
6849 if (!btf_type_is_struct(t))
6850 goto error;
6851
6852 off = (off - moff) % t->size;
6853 goto again;
6854
6855error:
6856 bpf_log(log, "access beyond struct %s at off %u size %u\n",
6857 tname, off, size);
6858 return -EACCES;
6859 }
6860
6861 for_each_member(i, t, member) {
6862 /* offset of the field in bytes */
6863 moff = __btf_member_bit_offset(t, member) / 8;
6864 if (off + size <= moff)
6865 /* won't find anything, field is already too far */
6866 break;
6867
6868 if (__btf_member_bitfield_size(t, member)) {
6869 u32 end_bit = __btf_member_bit_offset(t, member) +
6870 __btf_member_bitfield_size(t, member);
6871
6872 /* off <= moff instead of off == moff because clang
6873 * does not generate a BTF member for anonymous
6874 * bitfield like the ":16" here:
6875 * struct {
6876 * int :16;
6877 * int x:8;
6878 * };
6879 */
6880 if (off <= moff &&
6881 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6882 return WALK_SCALAR;
6883
6884 /* off may be accessing a following member
6885 *
6886 * or
6887 *
6888 * Doing partial access at either end of this
6889 * bitfield. Continue on this case also to
6890 * treat it as not accessing this bitfield
6891 * and eventually error out as field not
6892 * found to keep it simple.
6893 * It could be relaxed if there was a legit
6894 * partial access case later.
6895 */
6896 continue;
6897 }
6898
6899 /* In case of "off" is pointing to holes of a struct */
6900 if (off < moff)
6901 break;
6902
6903 /* type of the field */
6904 mid = member->type;
6905 mtype = btf_type_by_id(btf, member->type);
6906 mname = __btf_name_by_offset(btf, member->name_off);
6907
6908 mtype = __btf_resolve_size(btf, mtype, &msize,
6909 &elem_type, &elem_id, &total_nelems,
6910 &mid);
6911 if (IS_ERR(mtype)) {
6912 bpf_log(log, "field %s doesn't have size\n", mname);
6913 return -EFAULT;
6914 }
6915
6916 mtrue_end = moff + msize;
6917 if (off >= mtrue_end)
6918 /* no overlap with member, keep iterating */
6919 continue;
6920
6921 if (btf_type_is_array(mtype)) {
6922 u32 elem_idx;
6923
6924 /* __btf_resolve_size() above helps to
6925 * linearize a multi-dimensional array.
6926 *
6927 * The logic here is treating an array
6928 * in a struct as the following way:
6929 *
6930 * struct outer {
6931 * struct inner array[2][2];
6932 * };
6933 *
6934 * looks like:
6935 *
6936 * struct outer {
6937 * struct inner array_elem0;
6938 * struct inner array_elem1;
6939 * struct inner array_elem2;
6940 * struct inner array_elem3;
6941 * };
6942 *
6943 * When accessing outer->array[1][0], it moves
6944 * moff to "array_elem2", set mtype to
6945 * "struct inner", and msize also becomes
6946 * sizeof(struct inner). Then most of the
6947 * remaining logic will fall through without
6948 * caring the current member is an array or
6949 * not.
6950 *
6951 * Unlike mtype/msize/moff, mtrue_end does not
6952 * change. The naming difference ("_true") tells
6953 * that it is not always corresponding to
6954 * the current mtype/msize/moff.
6955 * It is the true end of the current
6956 * member (i.e. array in this case). That
6957 * will allow an int array to be accessed like
6958 * a scratch space,
6959 * i.e. allow access beyond the size of
6960 * the array's element as long as it is
6961 * within the mtrue_end boundary.
6962 */
6963
6964 /* skip empty array */
6965 if (moff == mtrue_end)
6966 continue;
6967
6968 msize /= total_nelems;
6969 elem_idx = (off - moff) / msize;
6970 moff += elem_idx * msize;
6971 mtype = elem_type;
6972 mid = elem_id;
6973 }
6974
6975 /* the 'off' we're looking for is either equal to start
6976 * of this field or inside of this struct
6977 */
6978 if (btf_type_is_struct(mtype)) {
6979 /* our field must be inside that union or struct */
6980 t = mtype;
6981
6982 /* return if the offset matches the member offset */
6983 if (off == moff) {
6984 *next_btf_id = mid;
6985 return WALK_STRUCT;
6986 }
6987
6988 /* adjust offset we're looking for */
6989 off -= moff;
6990 goto again;
6991 }
6992
6993 if (btf_type_is_ptr(mtype)) {
6994 const struct btf_type *stype, *t;
6995 enum bpf_type_flag tmp_flag = 0;
6996 u32 id;
6997
6998 if (msize != size || off != moff) {
6999 bpf_log(log,
7000 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
7001 mname, moff, tname, off, size);
7002 return -EACCES;
7003 }
7004
7005 /* check type tag */
7006 t = btf_type_by_id(btf, mtype->type);
7007 if (btf_type_is_type_tag(t)) {
7008 tag_value = __btf_name_by_offset(btf, t->name_off);
7009 /* check __user tag */
7010 if (strcmp(tag_value, "user") == 0)
7011 tmp_flag = MEM_USER;
7012 /* check __percpu tag */
7013 if (strcmp(tag_value, "percpu") == 0)
7014 tmp_flag = MEM_PERCPU;
7015 /* check __rcu tag */
7016 if (strcmp(tag_value, "rcu") == 0)
7017 tmp_flag = MEM_RCU;
7018 }
7019
7020 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
7021 if (btf_type_is_struct(stype)) {
7022 *next_btf_id = id;
7023 *flag |= tmp_flag;
7024 if (field_name)
7025 *field_name = mname;
7026 return WALK_PTR;
7027 }
7028 }
7029
7030 /* Allow more flexible access within an int as long as
7031 * it is within mtrue_end.
7032 * Since mtrue_end could be the end of an array,
7033 * that also allows using an array of int as a scratch
7034 * space. e.g. skb->cb[].
7035 */
7036 if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
7037 bpf_log(log,
7038 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
7039 mname, mtrue_end, tname, off, size);
7040 return -EACCES;
7041 }
7042
7043 return WALK_SCALAR;
7044 }
7045 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
7046 return -EINVAL;
7047}
7048
7049int btf_struct_access(struct bpf_verifier_log *log,
7050 const struct bpf_reg_state *reg,
7051 int off, int size, enum bpf_access_type atype __maybe_unused,
7052 u32 *next_btf_id, enum bpf_type_flag *flag,
7053 const char **field_name)
7054{
7055 const struct btf *btf = reg->btf;
7056 enum bpf_type_flag tmp_flag = 0;
7057 const struct btf_type *t;
7058 u32 id = reg->btf_id;
7059 int err;
7060
7061 while (type_is_alloc(reg->type)) {
7062 struct btf_struct_meta *meta;
7063 struct btf_record *rec;
7064 int i;
7065
7066 meta = btf_find_struct_meta(btf, id);
7067 if (!meta)
7068 break;
7069 rec = meta->record;
7070 for (i = 0; i < rec->cnt; i++) {
7071 struct btf_field *field = &rec->fields[i];
7072 u32 offset = field->offset;
7073 if (off < offset + field->size && offset < off + size) {
7074 bpf_log(log,
7075 "direct access to %s is disallowed\n",
7076 btf_field_type_name(field->type));
7077 return -EACCES;
7078 }
7079 }
7080 break;
7081 }
7082
7083 t = btf_type_by_id(btf, id);
7084 do {
7085 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
7086
7087 switch (err) {
7088 case WALK_PTR:
7089 /* For local types, the destination register cannot
7090 * become a pointer again.
7091 */
7092 if (type_is_alloc(reg->type))
7093 return SCALAR_VALUE;
7094 /* If we found the pointer or scalar on t+off,
7095 * we're done.
7096 */
7097 *next_btf_id = id;
7098 *flag = tmp_flag;
7099 return PTR_TO_BTF_ID;
7100 case WALK_SCALAR:
7101 return SCALAR_VALUE;
7102 case WALK_STRUCT:
7103 /* We found nested struct, so continue the search
7104 * by diving in it. At this point the offset is
7105 * aligned with the new type, so set it to 0.
7106 */
7107 t = btf_type_by_id(btf, id);
7108 off = 0;
7109 break;
7110 default:
7111 /* It's either error or unknown return value..
7112 * scream and leave.
7113 */
7114 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
7115 return -EINVAL;
7116 return err;
7117 }
7118 } while (t);
7119
7120 return -EINVAL;
7121}
7122
7123/* Check that two BTF types, each specified as an BTF object + id, are exactly
7124 * the same. Trivial ID check is not enough due to module BTFs, because we can
7125 * end up with two different module BTFs, but IDs point to the common type in
7126 * vmlinux BTF.
7127 */
7128bool btf_types_are_same(const struct btf *btf1, u32 id1,
7129 const struct btf *btf2, u32 id2)
7130{
7131 if (id1 != id2)
7132 return false;
7133 if (btf1 == btf2)
7134 return true;
7135 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
7136}
7137
7138bool btf_struct_ids_match(struct bpf_verifier_log *log,
7139 const struct btf *btf, u32 id, int off,
7140 const struct btf *need_btf, u32 need_type_id,
7141 bool strict)
7142{
7143 const struct btf_type *type;
7144 enum bpf_type_flag flag = 0;
7145 int err;
7146
7147 /* Are we already done? */
7148 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
7149 return true;
7150 /* In case of strict type match, we do not walk struct, the top level
7151 * type match must succeed. When strict is true, off should have already
7152 * been 0.
7153 */
7154 if (strict)
7155 return false;
7156again:
7157 type = btf_type_by_id(btf, id);
7158 if (!type)
7159 return false;
7160 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
7161 if (err != WALK_STRUCT)
7162 return false;
7163
7164 /* We found nested struct object. If it matches
7165 * the requested ID, we're done. Otherwise let's
7166 * continue the search with offset 0 in the new
7167 * type.
7168 */
7169 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
7170 off = 0;
7171 goto again;
7172 }
7173
7174 return true;
7175}
7176
7177static int __get_type_size(struct btf *btf, u32 btf_id,
7178 const struct btf_type **ret_type)
7179{
7180 const struct btf_type *t;
7181
7182 *ret_type = btf_type_by_id(btf, 0);
7183 if (!btf_id)
7184 /* void */
7185 return 0;
7186 t = btf_type_by_id(btf, btf_id);
7187 while (t && btf_type_is_modifier(t))
7188 t = btf_type_by_id(btf, t->type);
7189 if (!t)
7190 return -EINVAL;
7191 *ret_type = t;
7192 if (btf_type_is_ptr(t))
7193 /* kernel size of pointer. Not BPF's size of pointer*/
7194 return sizeof(void *);
7195 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
7196 return t->size;
7197 return -EINVAL;
7198}
7199
7200static u8 __get_type_fmodel_flags(const struct btf_type *t)
7201{
7202 u8 flags = 0;
7203
7204 if (__btf_type_is_struct(t))
7205 flags |= BTF_FMODEL_STRUCT_ARG;
7206 if (btf_type_is_signed_int(t))
7207 flags |= BTF_FMODEL_SIGNED_ARG;
7208
7209 return flags;
7210}
7211
7212int btf_distill_func_proto(struct bpf_verifier_log *log,
7213 struct btf *btf,
7214 const struct btf_type *func,
7215 const char *tname,
7216 struct btf_func_model *m)
7217{
7218 const struct btf_param *args;
7219 const struct btf_type *t;
7220 u32 i, nargs;
7221 int ret;
7222
7223 if (!func) {
7224 /* BTF function prototype doesn't match the verifier types.
7225 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
7226 */
7227 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
7228 m->arg_size[i] = 8;
7229 m->arg_flags[i] = 0;
7230 }
7231 m->ret_size = 8;
7232 m->ret_flags = 0;
7233 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
7234 return 0;
7235 }
7236 args = (const struct btf_param *)(func + 1);
7237 nargs = btf_type_vlen(func);
7238 if (nargs > MAX_BPF_FUNC_ARGS) {
7239 bpf_log(log,
7240 "The function %s has %d arguments. Too many.\n",
7241 tname, nargs);
7242 return -EINVAL;
7243 }
7244 ret = __get_type_size(btf, func->type, &t);
7245 if (ret < 0 || __btf_type_is_struct(t)) {
7246 bpf_log(log,
7247 "The function %s return type %s is unsupported.\n",
7248 tname, btf_type_str(t));
7249 return -EINVAL;
7250 }
7251 m->ret_size = ret;
7252 m->ret_flags = __get_type_fmodel_flags(t);
7253
7254 for (i = 0; i < nargs; i++) {
7255 if (i == nargs - 1 && args[i].type == 0) {
7256 bpf_log(log,
7257 "The function %s with variable args is unsupported.\n",
7258 tname);
7259 return -EINVAL;
7260 }
7261 ret = __get_type_size(btf, args[i].type, &t);
7262
7263 /* No support of struct argument size greater than 16 bytes */
7264 if (ret < 0 || ret > 16) {
7265 bpf_log(log,
7266 "The function %s arg%d type %s is unsupported.\n",
7267 tname, i, btf_type_str(t));
7268 return -EINVAL;
7269 }
7270 if (ret == 0) {
7271 bpf_log(log,
7272 "The function %s has malformed void argument.\n",
7273 tname);
7274 return -EINVAL;
7275 }
7276 m->arg_size[i] = ret;
7277 m->arg_flags[i] = __get_type_fmodel_flags(t);
7278 }
7279 m->nr_args = nargs;
7280 return 0;
7281}
7282
7283/* Compare BTFs of two functions assuming only scalars and pointers to context.
7284 * t1 points to BTF_KIND_FUNC in btf1
7285 * t2 points to BTF_KIND_FUNC in btf2
7286 * Returns:
7287 * EINVAL - function prototype mismatch
7288 * EFAULT - verifier bug
7289 * 0 - 99% match. The last 1% is validated by the verifier.
7290 */
7291static int btf_check_func_type_match(struct bpf_verifier_log *log,
7292 struct btf *btf1, const struct btf_type *t1,
7293 struct btf *btf2, const struct btf_type *t2)
7294{
7295 const struct btf_param *args1, *args2;
7296 const char *fn1, *fn2, *s1, *s2;
7297 u32 nargs1, nargs2, i;
7298
7299 fn1 = btf_name_by_offset(btf1, t1->name_off);
7300 fn2 = btf_name_by_offset(btf2, t2->name_off);
7301
7302 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
7303 bpf_log(log, "%s() is not a global function\n", fn1);
7304 return -EINVAL;
7305 }
7306 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
7307 bpf_log(log, "%s() is not a global function\n", fn2);
7308 return -EINVAL;
7309 }
7310
7311 t1 = btf_type_by_id(btf1, t1->type);
7312 if (!t1 || !btf_type_is_func_proto(t1))
7313 return -EFAULT;
7314 t2 = btf_type_by_id(btf2, t2->type);
7315 if (!t2 || !btf_type_is_func_proto(t2))
7316 return -EFAULT;
7317
7318 args1 = (const struct btf_param *)(t1 + 1);
7319 nargs1 = btf_type_vlen(t1);
7320 args2 = (const struct btf_param *)(t2 + 1);
7321 nargs2 = btf_type_vlen(t2);
7322
7323 if (nargs1 != nargs2) {
7324 bpf_log(log, "%s() has %d args while %s() has %d args\n",
7325 fn1, nargs1, fn2, nargs2);
7326 return -EINVAL;
7327 }
7328
7329 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7330 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7331 if (t1->info != t2->info) {
7332 bpf_log(log,
7333 "Return type %s of %s() doesn't match type %s of %s()\n",
7334 btf_type_str(t1), fn1,
7335 btf_type_str(t2), fn2);
7336 return -EINVAL;
7337 }
7338
7339 for (i = 0; i < nargs1; i++) {
7340 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
7341 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
7342
7343 if (t1->info != t2->info) {
7344 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
7345 i, fn1, btf_type_str(t1),
7346 fn2, btf_type_str(t2));
7347 return -EINVAL;
7348 }
7349 if (btf_type_has_size(t1) && t1->size != t2->size) {
7350 bpf_log(log,
7351 "arg%d in %s() has size %d while %s() has %d\n",
7352 i, fn1, t1->size,
7353 fn2, t2->size);
7354 return -EINVAL;
7355 }
7356
7357 /* global functions are validated with scalars and pointers
7358 * to context only. And only global functions can be replaced.
7359 * Hence type check only those types.
7360 */
7361 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
7362 continue;
7363 if (!btf_type_is_ptr(t1)) {
7364 bpf_log(log,
7365 "arg%d in %s() has unrecognized type\n",
7366 i, fn1);
7367 return -EINVAL;
7368 }
7369 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7370 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7371 if (!btf_type_is_struct(t1)) {
7372 bpf_log(log,
7373 "arg%d in %s() is not a pointer to context\n",
7374 i, fn1);
7375 return -EINVAL;
7376 }
7377 if (!btf_type_is_struct(t2)) {
7378 bpf_log(log,
7379 "arg%d in %s() is not a pointer to context\n",
7380 i, fn2);
7381 return -EINVAL;
7382 }
7383 /* This is an optional check to make program writing easier.
7384 * Compare names of structs and report an error to the user.
7385 * btf_prepare_func_args() already checked that t2 struct
7386 * is a context type. btf_prepare_func_args() will check
7387 * later that t1 struct is a context type as well.
7388 */
7389 s1 = btf_name_by_offset(btf1, t1->name_off);
7390 s2 = btf_name_by_offset(btf2, t2->name_off);
7391 if (strcmp(s1, s2)) {
7392 bpf_log(log,
7393 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
7394 i, fn1, s1, fn2, s2);
7395 return -EINVAL;
7396 }
7397 }
7398 return 0;
7399}
7400
7401/* Compare BTFs of given program with BTF of target program */
7402int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
7403 struct btf *btf2, const struct btf_type *t2)
7404{
7405 struct btf *btf1 = prog->aux->btf;
7406 const struct btf_type *t1;
7407 u32 btf_id = 0;
7408
7409 if (!prog->aux->func_info) {
7410 bpf_log(log, "Program extension requires BTF\n");
7411 return -EINVAL;
7412 }
7413
7414 btf_id = prog->aux->func_info[0].type_id;
7415 if (!btf_id)
7416 return -EFAULT;
7417
7418 t1 = btf_type_by_id(btf1, btf_id);
7419 if (!t1 || !btf_type_is_func(t1))
7420 return -EFAULT;
7421
7422 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
7423}
7424
7425static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
7426{
7427 const char *name;
7428
7429 t = btf_type_by_id(btf, t->type); /* skip PTR */
7430
7431 while (btf_type_is_modifier(t))
7432 t = btf_type_by_id(btf, t->type);
7433
7434 /* allow either struct or struct forward declaration */
7435 if (btf_type_is_struct(t) ||
7436 (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
7437 name = btf_str_by_offset(btf, t->name_off);
7438 return name && strcmp(name, "bpf_dynptr") == 0;
7439 }
7440
7441 return false;
7442}
7443
7444struct bpf_cand_cache {
7445 const char *name;
7446 u32 name_len;
7447 u16 kind;
7448 u16 cnt;
7449 struct {
7450 const struct btf *btf;
7451 u32 id;
7452 } cands[];
7453};
7454
7455static DEFINE_MUTEX(cand_cache_mutex);
7456
7457static struct bpf_cand_cache *
7458bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id);
7459
7460static int btf_get_ptr_to_btf_id(struct bpf_verifier_log *log, int arg_idx,
7461 const struct btf *btf, const struct btf_type *t)
7462{
7463 struct bpf_cand_cache *cc;
7464 struct bpf_core_ctx ctx = {
7465 .btf = btf,
7466 .log = log,
7467 };
7468 u32 kern_type_id, type_id;
7469 int err = 0;
7470
7471 /* skip PTR and modifiers */
7472 type_id = t->type;
7473 t = btf_type_by_id(btf, t->type);
7474 while (btf_type_is_modifier(t)) {
7475 type_id = t->type;
7476 t = btf_type_by_id(btf, t->type);
7477 }
7478
7479 mutex_lock(&cand_cache_mutex);
7480 cc = bpf_core_find_cands(&ctx, type_id);
7481 if (IS_ERR(cc)) {
7482 err = PTR_ERR(cc);
7483 bpf_log(log, "arg#%d reference type('%s %s') candidate matching error: %d\n",
7484 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7485 err);
7486 goto cand_cache_unlock;
7487 }
7488 if (cc->cnt != 1) {
7489 bpf_log(log, "arg#%d reference type('%s %s') %s\n",
7490 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7491 cc->cnt == 0 ? "has no matches" : "is ambiguous");
7492 err = cc->cnt == 0 ? -ENOENT : -ESRCH;
7493 goto cand_cache_unlock;
7494 }
7495 if (btf_is_module(cc->cands[0].btf)) {
7496 bpf_log(log, "arg#%d reference type('%s %s') points to kernel module type (unsupported)\n",
7497 arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off));
7498 err = -EOPNOTSUPP;
7499 goto cand_cache_unlock;
7500 }
7501 kern_type_id = cc->cands[0].id;
7502
7503cand_cache_unlock:
7504 mutex_unlock(&cand_cache_mutex);
7505 if (err)
7506 return err;
7507
7508 return kern_type_id;
7509}
7510
7511enum btf_arg_tag {
7512 ARG_TAG_CTX = BIT_ULL(0),
7513 ARG_TAG_NONNULL = BIT_ULL(1),
7514 ARG_TAG_TRUSTED = BIT_ULL(2),
7515 ARG_TAG_NULLABLE = BIT_ULL(3),
7516 ARG_TAG_ARENA = BIT_ULL(4),
7517};
7518
7519/* Process BTF of a function to produce high-level expectation of function
7520 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
7521 * is cached in subprog info for reuse.
7522 * Returns:
7523 * EFAULT - there is a verifier bug. Abort verification.
7524 * EINVAL - cannot convert BTF.
7525 * 0 - Successfully processed BTF and constructed argument expectations.
7526 */
7527int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
7528{
7529 bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
7530 struct bpf_subprog_info *sub = subprog_info(env, subprog);
7531 struct bpf_verifier_log *log = &env->log;
7532 struct bpf_prog *prog = env->prog;
7533 enum bpf_prog_type prog_type = prog->type;
7534 struct btf *btf = prog->aux->btf;
7535 const struct btf_param *args;
7536 const struct btf_type *t, *ref_t, *fn_t;
7537 u32 i, nargs, btf_id;
7538 const char *tname;
7539
7540 if (sub->args_cached)
7541 return 0;
7542
7543 if (!prog->aux->func_info) {
7544 bpf_log(log, "Verifier bug\n");
7545 return -EFAULT;
7546 }
7547
7548 btf_id = prog->aux->func_info[subprog].type_id;
7549 if (!btf_id) {
7550 if (!is_global) /* not fatal for static funcs */
7551 return -EINVAL;
7552 bpf_log(log, "Global functions need valid BTF\n");
7553 return -EFAULT;
7554 }
7555
7556 fn_t = btf_type_by_id(btf, btf_id);
7557 if (!fn_t || !btf_type_is_func(fn_t)) {
7558 /* These checks were already done by the verifier while loading
7559 * struct bpf_func_info
7560 */
7561 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
7562 subprog);
7563 return -EFAULT;
7564 }
7565 tname = btf_name_by_offset(btf, fn_t->name_off);
7566
7567 if (prog->aux->func_info_aux[subprog].unreliable) {
7568 bpf_log(log, "Verifier bug in function %s()\n", tname);
7569 return -EFAULT;
7570 }
7571 if (prog_type == BPF_PROG_TYPE_EXT)
7572 prog_type = prog->aux->dst_prog->type;
7573
7574 t = btf_type_by_id(btf, fn_t->type);
7575 if (!t || !btf_type_is_func_proto(t)) {
7576 bpf_log(log, "Invalid type of function %s()\n", tname);
7577 return -EFAULT;
7578 }
7579 args = (const struct btf_param *)(t + 1);
7580 nargs = btf_type_vlen(t);
7581 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7582 if (!is_global)
7583 return -EINVAL;
7584 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7585 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7586 return -EINVAL;
7587 }
7588 /* check that function returns int, exception cb also requires this */
7589 t = btf_type_by_id(btf, t->type);
7590 while (btf_type_is_modifier(t))
7591 t = btf_type_by_id(btf, t->type);
7592 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7593 if (!is_global)
7594 return -EINVAL;
7595 bpf_log(log,
7596 "Global function %s() doesn't return scalar. Only those are supported.\n",
7597 tname);
7598 return -EINVAL;
7599 }
7600 /* Convert BTF function arguments into verifier types.
7601 * Only PTR_TO_CTX and SCALAR are supported atm.
7602 */
7603 for (i = 0; i < nargs; i++) {
7604 u32 tags = 0;
7605 int id = 0;
7606
7607 /* 'arg:<tag>' decl_tag takes precedence over derivation of
7608 * register type from BTF type itself
7609 */
7610 while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) {
7611 const struct btf_type *tag_t = btf_type_by_id(btf, id);
7612 const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4;
7613
7614 /* disallow arg tags in static subprogs */
7615 if (!is_global) {
7616 bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7617 return -EOPNOTSUPP;
7618 }
7619
7620 if (strcmp(tag, "ctx") == 0) {
7621 tags |= ARG_TAG_CTX;
7622 } else if (strcmp(tag, "trusted") == 0) {
7623 tags |= ARG_TAG_TRUSTED;
7624 } else if (strcmp(tag, "nonnull") == 0) {
7625 tags |= ARG_TAG_NONNULL;
7626 } else if (strcmp(tag, "nullable") == 0) {
7627 tags |= ARG_TAG_NULLABLE;
7628 } else if (strcmp(tag, "arena") == 0) {
7629 tags |= ARG_TAG_ARENA;
7630 } else {
7631 bpf_log(log, "arg#%d has unsupported set of tags\n", i);
7632 return -EOPNOTSUPP;
7633 }
7634 }
7635 if (id != -ENOENT) {
7636 bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id);
7637 return id;
7638 }
7639
7640 t = btf_type_by_id(btf, args[i].type);
7641 while (btf_type_is_modifier(t))
7642 t = btf_type_by_id(btf, t->type);
7643 if (!btf_type_is_ptr(t))
7644 goto skip_pointer;
7645
7646 if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) {
7647 if (tags & ~ARG_TAG_CTX) {
7648 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7649 return -EINVAL;
7650 }
7651 if ((tags & ARG_TAG_CTX) &&
7652 btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7653 prog->expected_attach_type))
7654 return -EINVAL;
7655 sub->args[i].arg_type = ARG_PTR_TO_CTX;
7656 continue;
7657 }
7658 if (btf_is_dynptr_ptr(btf, t)) {
7659 if (tags) {
7660 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7661 return -EINVAL;
7662 }
7663 sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7664 continue;
7665 }
7666 if (tags & ARG_TAG_TRUSTED) {
7667 int kern_type_id;
7668
7669 if (tags & ARG_TAG_NONNULL) {
7670 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7671 return -EINVAL;
7672 }
7673
7674 kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t);
7675 if (kern_type_id < 0)
7676 return kern_type_id;
7677
7678 sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_TRUSTED;
7679 if (tags & ARG_TAG_NULLABLE)
7680 sub->args[i].arg_type |= PTR_MAYBE_NULL;
7681 sub->args[i].btf_id = kern_type_id;
7682 continue;
7683 }
7684 if (tags & ARG_TAG_ARENA) {
7685 if (tags & ~ARG_TAG_ARENA) {
7686 bpf_log(log, "arg#%d arena cannot be combined with any other tags\n", i);
7687 return -EINVAL;
7688 }
7689 sub->args[i].arg_type = ARG_PTR_TO_ARENA;
7690 continue;
7691 }
7692 if (is_global) { /* generic user data pointer */
7693 u32 mem_size;
7694
7695 if (tags & ARG_TAG_NULLABLE) {
7696 bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7697 return -EINVAL;
7698 }
7699
7700 t = btf_type_skip_modifiers(btf, t->type, NULL);
7701 ref_t = btf_resolve_size(btf, t, &mem_size);
7702 if (IS_ERR(ref_t)) {
7703 bpf_log(log, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7704 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7705 PTR_ERR(ref_t));
7706 return -EINVAL;
7707 }
7708
7709 sub->args[i].arg_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL;
7710 if (tags & ARG_TAG_NONNULL)
7711 sub->args[i].arg_type &= ~PTR_MAYBE_NULL;
7712 sub->args[i].mem_size = mem_size;
7713 continue;
7714 }
7715
7716skip_pointer:
7717 if (tags) {
7718 bpf_log(log, "arg#%d has pointer tag, but is not a pointer type\n", i);
7719 return -EINVAL;
7720 }
7721 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7722 sub->args[i].arg_type = ARG_ANYTHING;
7723 continue;
7724 }
7725 if (!is_global)
7726 return -EINVAL;
7727 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7728 i, btf_type_str(t), tname);
7729 return -EINVAL;
7730 }
7731
7732 sub->arg_cnt = nargs;
7733 sub->args_cached = true;
7734
7735 return 0;
7736}
7737
7738static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7739 struct btf_show *show)
7740{
7741 const struct btf_type *t = btf_type_by_id(btf, type_id);
7742
7743 show->btf = btf;
7744 memset(&show->state, 0, sizeof(show->state));
7745 memset(&show->obj, 0, sizeof(show->obj));
7746
7747 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7748}
7749
7750__printf(2, 0) static void btf_seq_show(struct btf_show *show, const char *fmt,
7751 va_list args)
7752{
7753 seq_vprintf((struct seq_file *)show->target, fmt, args);
7754}
7755
7756int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7757 void *obj, struct seq_file *m, u64 flags)
7758{
7759 struct btf_show sseq;
7760
7761 sseq.target = m;
7762 sseq.showfn = btf_seq_show;
7763 sseq.flags = flags;
7764
7765 btf_type_show(btf, type_id, obj, &sseq);
7766
7767 return sseq.state.status;
7768}
7769
7770void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7771 struct seq_file *m)
7772{
7773 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
7774 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7775 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7776}
7777
7778struct btf_show_snprintf {
7779 struct btf_show show;
7780 int len_left; /* space left in string */
7781 int len; /* length we would have written */
7782};
7783
7784__printf(2, 0) static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7785 va_list args)
7786{
7787 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7788 int len;
7789
7790 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7791
7792 if (len < 0) {
7793 ssnprintf->len_left = 0;
7794 ssnprintf->len = len;
7795 } else if (len >= ssnprintf->len_left) {
7796 /* no space, drive on to get length we would have written */
7797 ssnprintf->len_left = 0;
7798 ssnprintf->len += len;
7799 } else {
7800 ssnprintf->len_left -= len;
7801 ssnprintf->len += len;
7802 show->target += len;
7803 }
7804}
7805
7806int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7807 char *buf, int len, u64 flags)
7808{
7809 struct btf_show_snprintf ssnprintf;
7810
7811 ssnprintf.show.target = buf;
7812 ssnprintf.show.flags = flags;
7813 ssnprintf.show.showfn = btf_snprintf_show;
7814 ssnprintf.len_left = len;
7815 ssnprintf.len = 0;
7816
7817 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7818
7819 /* If we encountered an error, return it. */
7820 if (ssnprintf.show.state.status)
7821 return ssnprintf.show.state.status;
7822
7823 /* Otherwise return length we would have written */
7824 return ssnprintf.len;
7825}
7826
7827#ifdef CONFIG_PROC_FS
7828static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7829{
7830 const struct btf *btf = filp->private_data;
7831
7832 seq_printf(m, "btf_id:\t%u\n", btf->id);
7833}
7834#endif
7835
7836static int btf_release(struct inode *inode, struct file *filp)
7837{
7838 btf_put(filp->private_data);
7839 return 0;
7840}
7841
7842const struct file_operations btf_fops = {
7843#ifdef CONFIG_PROC_FS
7844 .show_fdinfo = bpf_btf_show_fdinfo,
7845#endif
7846 .release = btf_release,
7847};
7848
7849static int __btf_new_fd(struct btf *btf)
7850{
7851 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7852}
7853
7854int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
7855{
7856 struct btf *btf;
7857 int ret;
7858
7859 btf = btf_parse(attr, uattr, uattr_size);
7860 if (IS_ERR(btf))
7861 return PTR_ERR(btf);
7862
7863 ret = btf_alloc_id(btf);
7864 if (ret) {
7865 btf_free(btf);
7866 return ret;
7867 }
7868
7869 /*
7870 * The BTF ID is published to the userspace.
7871 * All BTF free must go through call_rcu() from
7872 * now on (i.e. free by calling btf_put()).
7873 */
7874
7875 ret = __btf_new_fd(btf);
7876 if (ret < 0)
7877 btf_put(btf);
7878
7879 return ret;
7880}
7881
7882struct btf *btf_get_by_fd(int fd)
7883{
7884 struct btf *btf;
7885 CLASS(fd, f)(fd);
7886
7887 if (fd_empty(f))
7888 return ERR_PTR(-EBADF);
7889
7890 if (fd_file(f)->f_op != &btf_fops)
7891 return ERR_PTR(-EINVAL);
7892
7893 btf = fd_file(f)->private_data;
7894 refcount_inc(&btf->refcnt);
7895
7896 return btf;
7897}
7898
7899int btf_get_info_by_fd(const struct btf *btf,
7900 const union bpf_attr *attr,
7901 union bpf_attr __user *uattr)
7902{
7903 struct bpf_btf_info __user *uinfo;
7904 struct bpf_btf_info info;
7905 u32 info_copy, btf_copy;
7906 void __user *ubtf;
7907 char __user *uname;
7908 u32 uinfo_len, uname_len, name_len;
7909 int ret = 0;
7910
7911 uinfo = u64_to_user_ptr(attr->info.info);
7912 uinfo_len = attr->info.info_len;
7913
7914 info_copy = min_t(u32, uinfo_len, sizeof(info));
7915 memset(&info, 0, sizeof(info));
7916 if (copy_from_user(&info, uinfo, info_copy))
7917 return -EFAULT;
7918
7919 info.id = btf->id;
7920 ubtf = u64_to_user_ptr(info.btf);
7921 btf_copy = min_t(u32, btf->data_size, info.btf_size);
7922 if (copy_to_user(ubtf, btf->data, btf_copy))
7923 return -EFAULT;
7924 info.btf_size = btf->data_size;
7925
7926 info.kernel_btf = btf->kernel_btf;
7927
7928 uname = u64_to_user_ptr(info.name);
7929 uname_len = info.name_len;
7930 if (!uname ^ !uname_len)
7931 return -EINVAL;
7932
7933 name_len = strlen(btf->name);
7934 info.name_len = name_len;
7935
7936 if (uname) {
7937 if (uname_len >= name_len + 1) {
7938 if (copy_to_user(uname, btf->name, name_len + 1))
7939 return -EFAULT;
7940 } else {
7941 char zero = '\0';
7942
7943 if (copy_to_user(uname, btf->name, uname_len - 1))
7944 return -EFAULT;
7945 if (put_user(zero, uname + uname_len - 1))
7946 return -EFAULT;
7947 /* let user-space know about too short buffer */
7948 ret = -ENOSPC;
7949 }
7950 }
7951
7952 if (copy_to_user(uinfo, &info, info_copy) ||
7953 put_user(info_copy, &uattr->info.info_len))
7954 return -EFAULT;
7955
7956 return ret;
7957}
7958
7959int btf_get_fd_by_id(u32 id)
7960{
7961 struct btf *btf;
7962 int fd;
7963
7964 rcu_read_lock();
7965 btf = idr_find(&btf_idr, id);
7966 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7967 btf = ERR_PTR(-ENOENT);
7968 rcu_read_unlock();
7969
7970 if (IS_ERR(btf))
7971 return PTR_ERR(btf);
7972
7973 fd = __btf_new_fd(btf);
7974 if (fd < 0)
7975 btf_put(btf);
7976
7977 return fd;
7978}
7979
7980u32 btf_obj_id(const struct btf *btf)
7981{
7982 return btf->id;
7983}
7984
7985bool btf_is_kernel(const struct btf *btf)
7986{
7987 return btf->kernel_btf;
7988}
7989
7990bool btf_is_module(const struct btf *btf)
7991{
7992 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7993}
7994
7995enum {
7996 BTF_MODULE_F_LIVE = (1 << 0),
7997};
7998
7999#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8000struct btf_module {
8001 struct list_head list;
8002 struct module *module;
8003 struct btf *btf;
8004 struct bin_attribute *sysfs_attr;
8005 int flags;
8006};
8007
8008static LIST_HEAD(btf_modules);
8009static DEFINE_MUTEX(btf_module_mutex);
8010
8011static ssize_t
8012btf_module_read(struct file *file, struct kobject *kobj,
8013 struct bin_attribute *bin_attr,
8014 char *buf, loff_t off, size_t len)
8015{
8016 const struct btf *btf = bin_attr->private;
8017
8018 memcpy(buf, btf->data + off, len);
8019 return len;
8020}
8021
8022static void purge_cand_cache(struct btf *btf);
8023
8024static int btf_module_notify(struct notifier_block *nb, unsigned long op,
8025 void *module)
8026{
8027 struct btf_module *btf_mod, *tmp;
8028 struct module *mod = module;
8029 struct btf *btf;
8030 int err = 0;
8031
8032 if (mod->btf_data_size == 0 ||
8033 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
8034 op != MODULE_STATE_GOING))
8035 goto out;
8036
8037 switch (op) {
8038 case MODULE_STATE_COMING:
8039 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
8040 if (!btf_mod) {
8041 err = -ENOMEM;
8042 goto out;
8043 }
8044 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size,
8045 mod->btf_base_data, mod->btf_base_data_size);
8046 if (IS_ERR(btf)) {
8047 kfree(btf_mod);
8048 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
8049 pr_warn("failed to validate module [%s] BTF: %ld\n",
8050 mod->name, PTR_ERR(btf));
8051 err = PTR_ERR(btf);
8052 } else {
8053 pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
8054 }
8055 goto out;
8056 }
8057 err = btf_alloc_id(btf);
8058 if (err) {
8059 btf_free(btf);
8060 kfree(btf_mod);
8061 goto out;
8062 }
8063
8064 purge_cand_cache(NULL);
8065 mutex_lock(&btf_module_mutex);
8066 btf_mod->module = module;
8067 btf_mod->btf = btf;
8068 list_add(&btf_mod->list, &btf_modules);
8069 mutex_unlock(&btf_module_mutex);
8070
8071 if (IS_ENABLED(CONFIG_SYSFS)) {
8072 struct bin_attribute *attr;
8073
8074 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
8075 if (!attr)
8076 goto out;
8077
8078 sysfs_bin_attr_init(attr);
8079 attr->attr.name = btf->name;
8080 attr->attr.mode = 0444;
8081 attr->size = btf->data_size;
8082 attr->private = btf;
8083 attr->read = btf_module_read;
8084
8085 err = sysfs_create_bin_file(btf_kobj, attr);
8086 if (err) {
8087 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
8088 mod->name, err);
8089 kfree(attr);
8090 err = 0;
8091 goto out;
8092 }
8093
8094 btf_mod->sysfs_attr = attr;
8095 }
8096
8097 break;
8098 case MODULE_STATE_LIVE:
8099 mutex_lock(&btf_module_mutex);
8100 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8101 if (btf_mod->module != module)
8102 continue;
8103
8104 btf_mod->flags |= BTF_MODULE_F_LIVE;
8105 break;
8106 }
8107 mutex_unlock(&btf_module_mutex);
8108 break;
8109 case MODULE_STATE_GOING:
8110 mutex_lock(&btf_module_mutex);
8111 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8112 if (btf_mod->module != module)
8113 continue;
8114
8115 list_del(&btf_mod->list);
8116 if (btf_mod->sysfs_attr)
8117 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
8118 purge_cand_cache(btf_mod->btf);
8119 btf_put(btf_mod->btf);
8120 kfree(btf_mod->sysfs_attr);
8121 kfree(btf_mod);
8122 break;
8123 }
8124 mutex_unlock(&btf_module_mutex);
8125 break;
8126 }
8127out:
8128 return notifier_from_errno(err);
8129}
8130
8131static struct notifier_block btf_module_nb = {
8132 .notifier_call = btf_module_notify,
8133};
8134
8135static int __init btf_module_init(void)
8136{
8137 register_module_notifier(&btf_module_nb);
8138 return 0;
8139}
8140
8141fs_initcall(btf_module_init);
8142#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
8143
8144struct module *btf_try_get_module(const struct btf *btf)
8145{
8146 struct module *res = NULL;
8147#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8148 struct btf_module *btf_mod, *tmp;
8149
8150 mutex_lock(&btf_module_mutex);
8151 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8152 if (btf_mod->btf != btf)
8153 continue;
8154
8155 /* We must only consider module whose __init routine has
8156 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
8157 * which is set from the notifier callback for
8158 * MODULE_STATE_LIVE.
8159 */
8160 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
8161 res = btf_mod->module;
8162
8163 break;
8164 }
8165 mutex_unlock(&btf_module_mutex);
8166#endif
8167
8168 return res;
8169}
8170
8171/* Returns struct btf corresponding to the struct module.
8172 * This function can return NULL or ERR_PTR.
8173 */
8174static struct btf *btf_get_module_btf(const struct module *module)
8175{
8176#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8177 struct btf_module *btf_mod, *tmp;
8178#endif
8179 struct btf *btf = NULL;
8180
8181 if (!module) {
8182 btf = bpf_get_btf_vmlinux();
8183 if (!IS_ERR_OR_NULL(btf))
8184 btf_get(btf);
8185 return btf;
8186 }
8187
8188#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8189 mutex_lock(&btf_module_mutex);
8190 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8191 if (btf_mod->module != module)
8192 continue;
8193
8194 btf_get(btf_mod->btf);
8195 btf = btf_mod->btf;
8196 break;
8197 }
8198 mutex_unlock(&btf_module_mutex);
8199#endif
8200
8201 return btf;
8202}
8203
8204static int check_btf_kconfigs(const struct module *module, const char *feature)
8205{
8206 if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
8207 pr_err("missing vmlinux BTF, cannot register %s\n", feature);
8208 return -ENOENT;
8209 }
8210 if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
8211 pr_warn("missing module BTF, cannot register %s\n", feature);
8212 return 0;
8213}
8214
8215BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
8216{
8217 struct btf *btf = NULL;
8218 int btf_obj_fd = 0;
8219 long ret;
8220
8221 if (flags)
8222 return -EINVAL;
8223
8224 if (name_sz <= 1 || name[name_sz - 1])
8225 return -EINVAL;
8226
8227 ret = bpf_find_btf_id(name, kind, &btf);
8228 if (ret > 0 && btf_is_module(btf)) {
8229 btf_obj_fd = __btf_new_fd(btf);
8230 if (btf_obj_fd < 0) {
8231 btf_put(btf);
8232 return btf_obj_fd;
8233 }
8234 return ret | (((u64)btf_obj_fd) << 32);
8235 }
8236 if (ret > 0)
8237 btf_put(btf);
8238 return ret;
8239}
8240
8241const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
8242 .func = bpf_btf_find_by_name_kind,
8243 .gpl_only = false,
8244 .ret_type = RET_INTEGER,
8245 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
8246 .arg2_type = ARG_CONST_SIZE,
8247 .arg3_type = ARG_ANYTHING,
8248 .arg4_type = ARG_ANYTHING,
8249};
8250
8251BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
8252#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
8253BTF_TRACING_TYPE_xxx
8254#undef BTF_TRACING_TYPE
8255
8256/* Validate well-formedness of iter argument type.
8257 * On success, return positive BTF ID of iter state's STRUCT type.
8258 * On error, negative error is returned.
8259 */
8260int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx)
8261{
8262 const struct btf_param *arg;
8263 const struct btf_type *t;
8264 const char *name;
8265 int btf_id;
8266
8267 if (btf_type_vlen(func) <= arg_idx)
8268 return -EINVAL;
8269
8270 arg = &btf_params(func)[arg_idx];
8271 t = btf_type_skip_modifiers(btf, arg->type, NULL);
8272 if (!t || !btf_type_is_ptr(t))
8273 return -EINVAL;
8274 t = btf_type_skip_modifiers(btf, t->type, &btf_id);
8275 if (!t || !__btf_type_is_struct(t))
8276 return -EINVAL;
8277
8278 name = btf_name_by_offset(btf, t->name_off);
8279 if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
8280 return -EINVAL;
8281
8282 return btf_id;
8283}
8284
8285static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
8286 const struct btf_type *func, u32 func_flags)
8287{
8288 u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
8289 const char *sfx, *iter_name;
8290 const struct btf_type *t;
8291 char exp_name[128];
8292 u32 nr_args;
8293 int btf_id;
8294
8295 /* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
8296 if (!flags || (flags & (flags - 1)))
8297 return -EINVAL;
8298
8299 /* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
8300 nr_args = btf_type_vlen(func);
8301 if (nr_args < 1)
8302 return -EINVAL;
8303
8304 btf_id = btf_check_iter_arg(btf, func, 0);
8305 if (btf_id < 0)
8306 return btf_id;
8307
8308 /* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
8309 * fit nicely in stack slots
8310 */
8311 t = btf_type_by_id(btf, btf_id);
8312 if (t->size == 0 || (t->size % 8))
8313 return -EINVAL;
8314
8315 /* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
8316 * naming pattern
8317 */
8318 iter_name = btf_name_by_offset(btf, t->name_off) + sizeof(ITER_PREFIX) - 1;
8319 if (flags & KF_ITER_NEW)
8320 sfx = "new";
8321 else if (flags & KF_ITER_NEXT)
8322 sfx = "next";
8323 else /* (flags & KF_ITER_DESTROY) */
8324 sfx = "destroy";
8325
8326 snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
8327 if (strcmp(func_name, exp_name))
8328 return -EINVAL;
8329
8330 /* only iter constructor should have extra arguments */
8331 if (!(flags & KF_ITER_NEW) && nr_args != 1)
8332 return -EINVAL;
8333
8334 if (flags & KF_ITER_NEXT) {
8335 /* bpf_iter_<type>_next() should return pointer */
8336 t = btf_type_skip_modifiers(btf, func->type, NULL);
8337 if (!t || !btf_type_is_ptr(t))
8338 return -EINVAL;
8339 }
8340
8341 if (flags & KF_ITER_DESTROY) {
8342 /* bpf_iter_<type>_destroy() should return void */
8343 t = btf_type_by_id(btf, func->type);
8344 if (!t || !btf_type_is_void(t))
8345 return -EINVAL;
8346 }
8347
8348 return 0;
8349}
8350
8351static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
8352{
8353 const struct btf_type *func;
8354 const char *func_name;
8355 int err;
8356
8357 /* any kfunc should be FUNC -> FUNC_PROTO */
8358 func = btf_type_by_id(btf, func_id);
8359 if (!func || !btf_type_is_func(func))
8360 return -EINVAL;
8361
8362 /* sanity check kfunc name */
8363 func_name = btf_name_by_offset(btf, func->name_off);
8364 if (!func_name || !func_name[0])
8365 return -EINVAL;
8366
8367 func = btf_type_by_id(btf, func->type);
8368 if (!func || !btf_type_is_func_proto(func))
8369 return -EINVAL;
8370
8371 if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
8372 err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
8373 if (err)
8374 return err;
8375 }
8376
8377 return 0;
8378}
8379
8380/* Kernel Function (kfunc) BTF ID set registration API */
8381
8382static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
8383 const struct btf_kfunc_id_set *kset)
8384{
8385 struct btf_kfunc_hook_filter *hook_filter;
8386 struct btf_id_set8 *add_set = kset->set;
8387 bool vmlinux_set = !btf_is_module(btf);
8388 bool add_filter = !!kset->filter;
8389 struct btf_kfunc_set_tab *tab;
8390 struct btf_id_set8 *set;
8391 u32 set_cnt, i;
8392 int ret;
8393
8394 if (hook >= BTF_KFUNC_HOOK_MAX) {
8395 ret = -EINVAL;
8396 goto end;
8397 }
8398
8399 if (!add_set->cnt)
8400 return 0;
8401
8402 tab = btf->kfunc_set_tab;
8403
8404 if (tab && add_filter) {
8405 u32 i;
8406
8407 hook_filter = &tab->hook_filters[hook];
8408 for (i = 0; i < hook_filter->nr_filters; i++) {
8409 if (hook_filter->filters[i] == kset->filter) {
8410 add_filter = false;
8411 break;
8412 }
8413 }
8414
8415 if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
8416 ret = -E2BIG;
8417 goto end;
8418 }
8419 }
8420
8421 if (!tab) {
8422 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
8423 if (!tab)
8424 return -ENOMEM;
8425 btf->kfunc_set_tab = tab;
8426 }
8427
8428 set = tab->sets[hook];
8429 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
8430 * for module sets.
8431 */
8432 if (WARN_ON_ONCE(set && !vmlinux_set)) {
8433 ret = -EINVAL;
8434 goto end;
8435 }
8436
8437 /* In case of vmlinux sets, there may be more than one set being
8438 * registered per hook. To create a unified set, we allocate a new set
8439 * and concatenate all individual sets being registered. While each set
8440 * is individually sorted, they may become unsorted when concatenated,
8441 * hence re-sorting the final set again is required to make binary
8442 * searching the set using btf_id_set8_contains function work.
8443 *
8444 * For module sets, we need to allocate as we may need to relocate
8445 * BTF ids.
8446 */
8447 set_cnt = set ? set->cnt : 0;
8448
8449 if (set_cnt > U32_MAX - add_set->cnt) {
8450 ret = -EOVERFLOW;
8451 goto end;
8452 }
8453
8454 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
8455 ret = -E2BIG;
8456 goto end;
8457 }
8458
8459 /* Grow set */
8460 set = krealloc(tab->sets[hook],
8461 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
8462 GFP_KERNEL | __GFP_NOWARN);
8463 if (!set) {
8464 ret = -ENOMEM;
8465 goto end;
8466 }
8467
8468 /* For newly allocated set, initialize set->cnt to 0 */
8469 if (!tab->sets[hook])
8470 set->cnt = 0;
8471 tab->sets[hook] = set;
8472
8473 /* Concatenate the two sets */
8474 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
8475 /* Now that the set is copied, update with relocated BTF ids */
8476 for (i = set->cnt; i < set->cnt + add_set->cnt; i++)
8477 set->pairs[i].id = btf_relocate_id(btf, set->pairs[i].id);
8478
8479 set->cnt += add_set->cnt;
8480
8481 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
8482
8483 if (add_filter) {
8484 hook_filter = &tab->hook_filters[hook];
8485 hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
8486 }
8487 return 0;
8488end:
8489 btf_free_kfunc_set_tab(btf);
8490 return ret;
8491}
8492
8493static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
8494 enum btf_kfunc_hook hook,
8495 u32 kfunc_btf_id,
8496 const struct bpf_prog *prog)
8497{
8498 struct btf_kfunc_hook_filter *hook_filter;
8499 struct btf_id_set8 *set;
8500 u32 *id, i;
8501
8502 if (hook >= BTF_KFUNC_HOOK_MAX)
8503 return NULL;
8504 if (!btf->kfunc_set_tab)
8505 return NULL;
8506 hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
8507 for (i = 0; i < hook_filter->nr_filters; i++) {
8508 if (hook_filter->filters[i](prog, kfunc_btf_id))
8509 return NULL;
8510 }
8511 set = btf->kfunc_set_tab->sets[hook];
8512 if (!set)
8513 return NULL;
8514 id = btf_id_set8_contains(set, kfunc_btf_id);
8515 if (!id)
8516 return NULL;
8517 /* The flags for BTF ID are located next to it */
8518 return id + 1;
8519}
8520
8521static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
8522{
8523 switch (prog_type) {
8524 case BPF_PROG_TYPE_UNSPEC:
8525 return BTF_KFUNC_HOOK_COMMON;
8526 case BPF_PROG_TYPE_XDP:
8527 return BTF_KFUNC_HOOK_XDP;
8528 case BPF_PROG_TYPE_SCHED_CLS:
8529 return BTF_KFUNC_HOOK_TC;
8530 case BPF_PROG_TYPE_STRUCT_OPS:
8531 return BTF_KFUNC_HOOK_STRUCT_OPS;
8532 case BPF_PROG_TYPE_TRACING:
8533 case BPF_PROG_TYPE_TRACEPOINT:
8534 case BPF_PROG_TYPE_PERF_EVENT:
8535 case BPF_PROG_TYPE_LSM:
8536 return BTF_KFUNC_HOOK_TRACING;
8537 case BPF_PROG_TYPE_SYSCALL:
8538 return BTF_KFUNC_HOOK_SYSCALL;
8539 case BPF_PROG_TYPE_CGROUP_SKB:
8540 case BPF_PROG_TYPE_CGROUP_SOCK:
8541 case BPF_PROG_TYPE_CGROUP_DEVICE:
8542 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
8543 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
8544 case BPF_PROG_TYPE_CGROUP_SYSCTL:
8545 return BTF_KFUNC_HOOK_CGROUP;
8546 case BPF_PROG_TYPE_SCHED_ACT:
8547 return BTF_KFUNC_HOOK_SCHED_ACT;
8548 case BPF_PROG_TYPE_SK_SKB:
8549 return BTF_KFUNC_HOOK_SK_SKB;
8550 case BPF_PROG_TYPE_SOCKET_FILTER:
8551 return BTF_KFUNC_HOOK_SOCKET_FILTER;
8552 case BPF_PROG_TYPE_LWT_OUT:
8553 case BPF_PROG_TYPE_LWT_IN:
8554 case BPF_PROG_TYPE_LWT_XMIT:
8555 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
8556 return BTF_KFUNC_HOOK_LWT;
8557 case BPF_PROG_TYPE_NETFILTER:
8558 return BTF_KFUNC_HOOK_NETFILTER;
8559 case BPF_PROG_TYPE_KPROBE:
8560 return BTF_KFUNC_HOOK_KPROBE;
8561 default:
8562 return BTF_KFUNC_HOOK_MAX;
8563 }
8564}
8565
8566/* Caution:
8567 * Reference to the module (obtained using btf_try_get_module) corresponding to
8568 * the struct btf *MUST* be held when calling this function from verifier
8569 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
8570 * keeping the reference for the duration of the call provides the necessary
8571 * protection for looking up a well-formed btf->kfunc_set_tab.
8572 */
8573u32 *btf_kfunc_id_set_contains(const struct btf *btf,
8574 u32 kfunc_btf_id,
8575 const struct bpf_prog *prog)
8576{
8577 enum bpf_prog_type prog_type = resolve_prog_type(prog);
8578 enum btf_kfunc_hook hook;
8579 u32 *kfunc_flags;
8580
8581 kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
8582 if (kfunc_flags)
8583 return kfunc_flags;
8584
8585 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8586 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
8587}
8588
8589u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
8590 const struct bpf_prog *prog)
8591{
8592 return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
8593}
8594
8595static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
8596 const struct btf_kfunc_id_set *kset)
8597{
8598 struct btf *btf;
8599 int ret, i;
8600
8601 btf = btf_get_module_btf(kset->owner);
8602 if (!btf)
8603 return check_btf_kconfigs(kset->owner, "kfunc");
8604 if (IS_ERR(btf))
8605 return PTR_ERR(btf);
8606
8607 for (i = 0; i < kset->set->cnt; i++) {
8608 ret = btf_check_kfunc_protos(btf, btf_relocate_id(btf, kset->set->pairs[i].id),
8609 kset->set->pairs[i].flags);
8610 if (ret)
8611 goto err_out;
8612 }
8613
8614 ret = btf_populate_kfunc_set(btf, hook, kset);
8615
8616err_out:
8617 btf_put(btf);
8618 return ret;
8619}
8620
8621/* This function must be invoked only from initcalls/module init functions */
8622int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
8623 const struct btf_kfunc_id_set *kset)
8624{
8625 enum btf_kfunc_hook hook;
8626
8627 /* All kfuncs need to be tagged as such in BTF.
8628 * WARN() for initcall registrations that do not check errors.
8629 */
8630 if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
8631 WARN_ON(!kset->owner);
8632 return -EINVAL;
8633 }
8634
8635 hook = bpf_prog_type_to_kfunc_hook(prog_type);
8636 return __register_btf_kfunc_id_set(hook, kset);
8637}
8638EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
8639
8640/* This function must be invoked only from initcalls/module init functions */
8641int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
8642{
8643 return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
8644}
8645EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
8646
8647s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
8648{
8649 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
8650 struct btf_id_dtor_kfunc *dtor;
8651
8652 if (!tab)
8653 return -ENOENT;
8654 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8655 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8656 */
8657 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8658 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8659 if (!dtor)
8660 return -ENOENT;
8661 return dtor->kfunc_btf_id;
8662}
8663
8664static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8665{
8666 const struct btf_type *dtor_func, *dtor_func_proto, *t;
8667 const struct btf_param *args;
8668 s32 dtor_btf_id;
8669 u32 nr_args, i;
8670
8671 for (i = 0; i < cnt; i++) {
8672 dtor_btf_id = btf_relocate_id(btf, dtors[i].kfunc_btf_id);
8673
8674 dtor_func = btf_type_by_id(btf, dtor_btf_id);
8675 if (!dtor_func || !btf_type_is_func(dtor_func))
8676 return -EINVAL;
8677
8678 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8679 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8680 return -EINVAL;
8681
8682 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8683 t = btf_type_by_id(btf, dtor_func_proto->type);
8684 if (!t || !btf_type_is_void(t))
8685 return -EINVAL;
8686
8687 nr_args = btf_type_vlen(dtor_func_proto);
8688 if (nr_args != 1)
8689 return -EINVAL;
8690 args = btf_params(dtor_func_proto);
8691 t = btf_type_by_id(btf, args[0].type);
8692 /* Allow any pointer type, as width on targets Linux supports
8693 * will be same for all pointer types (i.e. sizeof(void *))
8694 */
8695 if (!t || !btf_type_is_ptr(t))
8696 return -EINVAL;
8697 }
8698 return 0;
8699}
8700
8701/* This function must be invoked only from initcalls/module init functions */
8702int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8703 struct module *owner)
8704{
8705 struct btf_id_dtor_kfunc_tab *tab;
8706 struct btf *btf;
8707 u32 tab_cnt, i;
8708 int ret;
8709
8710 btf = btf_get_module_btf(owner);
8711 if (!btf)
8712 return check_btf_kconfigs(owner, "dtor kfuncs");
8713 if (IS_ERR(btf))
8714 return PTR_ERR(btf);
8715
8716 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8717 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8718 ret = -E2BIG;
8719 goto end;
8720 }
8721
8722 /* Ensure that the prototype of dtor kfuncs being registered is sane */
8723 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8724 if (ret < 0)
8725 goto end;
8726
8727 tab = btf->dtor_kfunc_tab;
8728 /* Only one call allowed for modules */
8729 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8730 ret = -EINVAL;
8731 goto end;
8732 }
8733
8734 tab_cnt = tab ? tab->cnt : 0;
8735 if (tab_cnt > U32_MAX - add_cnt) {
8736 ret = -EOVERFLOW;
8737 goto end;
8738 }
8739 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8740 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8741 ret = -E2BIG;
8742 goto end;
8743 }
8744
8745 tab = krealloc(btf->dtor_kfunc_tab,
8746 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
8747 GFP_KERNEL | __GFP_NOWARN);
8748 if (!tab) {
8749 ret = -ENOMEM;
8750 goto end;
8751 }
8752
8753 if (!btf->dtor_kfunc_tab)
8754 tab->cnt = 0;
8755 btf->dtor_kfunc_tab = tab;
8756
8757 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8758
8759 /* remap BTF ids based on BTF relocation (if any) */
8760 for (i = tab_cnt; i < tab_cnt + add_cnt; i++) {
8761 tab->dtors[i].btf_id = btf_relocate_id(btf, tab->dtors[i].btf_id);
8762 tab->dtors[i].kfunc_btf_id = btf_relocate_id(btf, tab->dtors[i].kfunc_btf_id);
8763 }
8764
8765 tab->cnt += add_cnt;
8766
8767 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8768
8769end:
8770 if (ret)
8771 btf_free_dtor_kfunc_tab(btf);
8772 btf_put(btf);
8773 return ret;
8774}
8775EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8776
8777#define MAX_TYPES_ARE_COMPAT_DEPTH 2
8778
8779/* Check local and target types for compatibility. This check is used for
8780 * type-based CO-RE relocations and follow slightly different rules than
8781 * field-based relocations. This function assumes that root types were already
8782 * checked for name match. Beyond that initial root-level name check, names
8783 * are completely ignored. Compatibility rules are as follows:
8784 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8785 * kind should match for local and target types (i.e., STRUCT is not
8786 * compatible with UNION);
8787 * - for ENUMs/ENUM64s, the size is ignored;
8788 * - for INT, size and signedness are ignored;
8789 * - for ARRAY, dimensionality is ignored, element types are checked for
8790 * compatibility recursively;
8791 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
8792 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8793 * - FUNC_PROTOs are compatible if they have compatible signature: same
8794 * number of input args and compatible return and argument types.
8795 * These rules are not set in stone and probably will be adjusted as we get
8796 * more experience with using BPF CO-RE relocations.
8797 */
8798int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8799 const struct btf *targ_btf, __u32 targ_id)
8800{
8801 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8802 MAX_TYPES_ARE_COMPAT_DEPTH);
8803}
8804
8805#define MAX_TYPES_MATCH_DEPTH 2
8806
8807int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8808 const struct btf *targ_btf, u32 targ_id)
8809{
8810 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8811 MAX_TYPES_MATCH_DEPTH);
8812}
8813
8814static bool bpf_core_is_flavor_sep(const char *s)
8815{
8816 /* check X___Y name pattern, where X and Y are not underscores */
8817 return s[0] != '_' && /* X */
8818 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
8819 s[4] != '_'; /* Y */
8820}
8821
8822size_t bpf_core_essential_name_len(const char *name)
8823{
8824 size_t n = strlen(name);
8825 int i;
8826
8827 for (i = n - 5; i >= 0; i--) {
8828 if (bpf_core_is_flavor_sep(name + i))
8829 return i + 1;
8830 }
8831 return n;
8832}
8833
8834static void bpf_free_cands(struct bpf_cand_cache *cands)
8835{
8836 if (!cands->cnt)
8837 /* empty candidate array was allocated on stack */
8838 return;
8839 kfree(cands);
8840}
8841
8842static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
8843{
8844 kfree(cands->name);
8845 kfree(cands);
8846}
8847
8848#define VMLINUX_CAND_CACHE_SIZE 31
8849static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
8850
8851#define MODULE_CAND_CACHE_SIZE 31
8852static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
8853
8854static void __print_cand_cache(struct bpf_verifier_log *log,
8855 struct bpf_cand_cache **cache,
8856 int cache_size)
8857{
8858 struct bpf_cand_cache *cc;
8859 int i, j;
8860
8861 for (i = 0; i < cache_size; i++) {
8862 cc = cache[i];
8863 if (!cc)
8864 continue;
8865 bpf_log(log, "[%d]%s(", i, cc->name);
8866 for (j = 0; j < cc->cnt; j++) {
8867 bpf_log(log, "%d", cc->cands[j].id);
8868 if (j < cc->cnt - 1)
8869 bpf_log(log, " ");
8870 }
8871 bpf_log(log, "), ");
8872 }
8873}
8874
8875static void print_cand_cache(struct bpf_verifier_log *log)
8876{
8877 mutex_lock(&cand_cache_mutex);
8878 bpf_log(log, "vmlinux_cand_cache:");
8879 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8880 bpf_log(log, "\nmodule_cand_cache:");
8881 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8882 bpf_log(log, "\n");
8883 mutex_unlock(&cand_cache_mutex);
8884}
8885
8886static u32 hash_cands(struct bpf_cand_cache *cands)
8887{
8888 return jhash(cands->name, cands->name_len, 0);
8889}
8890
8891static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
8892 struct bpf_cand_cache **cache,
8893 int cache_size)
8894{
8895 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
8896
8897 if (cc && cc->name_len == cands->name_len &&
8898 !strncmp(cc->name, cands->name, cands->name_len))
8899 return cc;
8900 return NULL;
8901}
8902
8903static size_t sizeof_cands(int cnt)
8904{
8905 return offsetof(struct bpf_cand_cache, cands[cnt]);
8906}
8907
8908static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
8909 struct bpf_cand_cache **cache,
8910 int cache_size)
8911{
8912 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
8913
8914 if (*cc) {
8915 bpf_free_cands_from_cache(*cc);
8916 *cc = NULL;
8917 }
8918 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
8919 if (!new_cands) {
8920 bpf_free_cands(cands);
8921 return ERR_PTR(-ENOMEM);
8922 }
8923 /* strdup the name, since it will stay in cache.
8924 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
8925 */
8926 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
8927 bpf_free_cands(cands);
8928 if (!new_cands->name) {
8929 kfree(new_cands);
8930 return ERR_PTR(-ENOMEM);
8931 }
8932 *cc = new_cands;
8933 return new_cands;
8934}
8935
8936#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8937static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
8938 int cache_size)
8939{
8940 struct bpf_cand_cache *cc;
8941 int i, j;
8942
8943 for (i = 0; i < cache_size; i++) {
8944 cc = cache[i];
8945 if (!cc)
8946 continue;
8947 if (!btf) {
8948 /* when new module is loaded purge all of module_cand_cache,
8949 * since new module might have candidates with the name
8950 * that matches cached cands.
8951 */
8952 bpf_free_cands_from_cache(cc);
8953 cache[i] = NULL;
8954 continue;
8955 }
8956 /* when module is unloaded purge cache entries
8957 * that match module's btf
8958 */
8959 for (j = 0; j < cc->cnt; j++)
8960 if (cc->cands[j].btf == btf) {
8961 bpf_free_cands_from_cache(cc);
8962 cache[i] = NULL;
8963 break;
8964 }
8965 }
8966
8967}
8968
8969static void purge_cand_cache(struct btf *btf)
8970{
8971 mutex_lock(&cand_cache_mutex);
8972 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8973 mutex_unlock(&cand_cache_mutex);
8974}
8975#endif
8976
8977static struct bpf_cand_cache *
8978bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8979 int targ_start_id)
8980{
8981 struct bpf_cand_cache *new_cands;
8982 const struct btf_type *t;
8983 const char *targ_name;
8984 size_t targ_essent_len;
8985 int n, i;
8986
8987 n = btf_nr_types(targ_btf);
8988 for (i = targ_start_id; i < n; i++) {
8989 t = btf_type_by_id(targ_btf, i);
8990 if (btf_kind(t) != cands->kind)
8991 continue;
8992
8993 targ_name = btf_name_by_offset(targ_btf, t->name_off);
8994 if (!targ_name)
8995 continue;
8996
8997 /* the resched point is before strncmp to make sure that search
8998 * for non-existing name will have a chance to schedule().
8999 */
9000 cond_resched();
9001
9002 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
9003 continue;
9004
9005 targ_essent_len = bpf_core_essential_name_len(targ_name);
9006 if (targ_essent_len != cands->name_len)
9007 continue;
9008
9009 /* most of the time there is only one candidate for a given kind+name pair */
9010 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
9011 if (!new_cands) {
9012 bpf_free_cands(cands);
9013 return ERR_PTR(-ENOMEM);
9014 }
9015
9016 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
9017 bpf_free_cands(cands);
9018 cands = new_cands;
9019 cands->cands[cands->cnt].btf = targ_btf;
9020 cands->cands[cands->cnt].id = i;
9021 cands->cnt++;
9022 }
9023 return cands;
9024}
9025
9026static struct bpf_cand_cache *
9027bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
9028{
9029 struct bpf_cand_cache *cands, *cc, local_cand = {};
9030 const struct btf *local_btf = ctx->btf;
9031 const struct btf_type *local_type;
9032 const struct btf *main_btf;
9033 size_t local_essent_len;
9034 struct btf *mod_btf;
9035 const char *name;
9036 int id;
9037
9038 main_btf = bpf_get_btf_vmlinux();
9039 if (IS_ERR(main_btf))
9040 return ERR_CAST(main_btf);
9041 if (!main_btf)
9042 return ERR_PTR(-EINVAL);
9043
9044 local_type = btf_type_by_id(local_btf, local_type_id);
9045 if (!local_type)
9046 return ERR_PTR(-EINVAL);
9047
9048 name = btf_name_by_offset(local_btf, local_type->name_off);
9049 if (str_is_empty(name))
9050 return ERR_PTR(-EINVAL);
9051 local_essent_len = bpf_core_essential_name_len(name);
9052
9053 cands = &local_cand;
9054 cands->name = name;
9055 cands->kind = btf_kind(local_type);
9056 cands->name_len = local_essent_len;
9057
9058 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
9059 /* cands is a pointer to stack here */
9060 if (cc) {
9061 if (cc->cnt)
9062 return cc;
9063 goto check_modules;
9064 }
9065
9066 /* Attempt to find target candidates in vmlinux BTF first */
9067 cands = bpf_core_add_cands(cands, main_btf, 1);
9068 if (IS_ERR(cands))
9069 return ERR_CAST(cands);
9070
9071 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
9072
9073 /* populate cache even when cands->cnt == 0 */
9074 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
9075 if (IS_ERR(cc))
9076 return ERR_CAST(cc);
9077
9078 /* if vmlinux BTF has any candidate, don't go for module BTFs */
9079 if (cc->cnt)
9080 return cc;
9081
9082check_modules:
9083 /* cands is a pointer to stack here and cands->cnt == 0 */
9084 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9085 if (cc)
9086 /* if cache has it return it even if cc->cnt == 0 */
9087 return cc;
9088
9089 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
9090 spin_lock_bh(&btf_idr_lock);
9091 idr_for_each_entry(&btf_idr, mod_btf, id) {
9092 if (!btf_is_module(mod_btf))
9093 continue;
9094 /* linear search could be slow hence unlock/lock
9095 * the IDR to avoiding holding it for too long
9096 */
9097 btf_get(mod_btf);
9098 spin_unlock_bh(&btf_idr_lock);
9099 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
9100 btf_put(mod_btf);
9101 if (IS_ERR(cands))
9102 return ERR_CAST(cands);
9103 spin_lock_bh(&btf_idr_lock);
9104 }
9105 spin_unlock_bh(&btf_idr_lock);
9106 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
9107 * or pointer to stack if cands->cnd == 0.
9108 * Copy it into the cache even when cands->cnt == 0 and
9109 * return the result.
9110 */
9111 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9112}
9113
9114int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
9115 int relo_idx, void *insn)
9116{
9117 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
9118 struct bpf_core_cand_list cands = {};
9119 struct bpf_core_relo_res targ_res;
9120 struct bpf_core_spec *specs;
9121 const struct btf_type *type;
9122 int err;
9123
9124 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
9125 * into arrays of btf_ids of struct fields and array indices.
9126 */
9127 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
9128 if (!specs)
9129 return -ENOMEM;
9130
9131 type = btf_type_by_id(ctx->btf, relo->type_id);
9132 if (!type) {
9133 bpf_log(ctx->log, "relo #%u: bad type id %u\n",
9134 relo_idx, relo->type_id);
9135 kfree(specs);
9136 return -EINVAL;
9137 }
9138
9139 if (need_cands) {
9140 struct bpf_cand_cache *cc;
9141 int i;
9142
9143 mutex_lock(&cand_cache_mutex);
9144 cc = bpf_core_find_cands(ctx, relo->type_id);
9145 if (IS_ERR(cc)) {
9146 bpf_log(ctx->log, "target candidate search failed for %d\n",
9147 relo->type_id);
9148 err = PTR_ERR(cc);
9149 goto out;
9150 }
9151 if (cc->cnt) {
9152 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
9153 if (!cands.cands) {
9154 err = -ENOMEM;
9155 goto out;
9156 }
9157 }
9158 for (i = 0; i < cc->cnt; i++) {
9159 bpf_log(ctx->log,
9160 "CO-RE relocating %s %s: found target candidate [%d]\n",
9161 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
9162 cands.cands[i].btf = cc->cands[i].btf;
9163 cands.cands[i].id = cc->cands[i].id;
9164 }
9165 cands.len = cc->cnt;
9166 /* cand_cache_mutex needs to span the cache lookup and
9167 * copy of btf pointer into bpf_core_cand_list,
9168 * since module can be unloaded while bpf_core_calc_relo_insn
9169 * is working with module's btf.
9170 */
9171 }
9172
9173 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
9174 &targ_res);
9175 if (err)
9176 goto out;
9177
9178 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
9179 &targ_res);
9180
9181out:
9182 kfree(specs);
9183 if (need_cands) {
9184 kfree(cands.cands);
9185 mutex_unlock(&cand_cache_mutex);
9186 if (ctx->log->level & BPF_LOG_LEVEL2)
9187 print_cand_cache(ctx->log);
9188 }
9189 return err;
9190}
9191
9192bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
9193 const struct bpf_reg_state *reg,
9194 const char *field_name, u32 btf_id, const char *suffix)
9195{
9196 struct btf *btf = reg->btf;
9197 const struct btf_type *walk_type, *safe_type;
9198 const char *tname;
9199 char safe_tname[64];
9200 long ret, safe_id;
9201 const struct btf_member *member;
9202 u32 i;
9203
9204 walk_type = btf_type_by_id(btf, reg->btf_id);
9205 if (!walk_type)
9206 return false;
9207
9208 tname = btf_name_by_offset(btf, walk_type->name_off);
9209
9210 ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
9211 if (ret >= sizeof(safe_tname))
9212 return false;
9213
9214 safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
9215 if (safe_id < 0)
9216 return false;
9217
9218 safe_type = btf_type_by_id(btf, safe_id);
9219 if (!safe_type)
9220 return false;
9221
9222 for_each_member(i, safe_type, member) {
9223 const char *m_name = __btf_name_by_offset(btf, member->name_off);
9224 const struct btf_type *mtype = btf_type_by_id(btf, member->type);
9225 u32 id;
9226
9227 if (!btf_type_is_ptr(mtype))
9228 continue;
9229
9230 btf_type_skip_modifiers(btf, mtype->type, &id);
9231 /* If we match on both type and name, the field is considered trusted. */
9232 if (btf_id == id && !strcmp(field_name, m_name))
9233 return true;
9234 }
9235
9236 return false;
9237}
9238
9239bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
9240 const struct btf *reg_btf, u32 reg_id,
9241 const struct btf *arg_btf, u32 arg_id)
9242{
9243 const char *reg_name, *arg_name, *search_needle;
9244 const struct btf_type *reg_type, *arg_type;
9245 int reg_len, arg_len, cmp_len;
9246 size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
9247
9248 reg_type = btf_type_by_id(reg_btf, reg_id);
9249 if (!reg_type)
9250 return false;
9251
9252 arg_type = btf_type_by_id(arg_btf, arg_id);
9253 if (!arg_type)
9254 return false;
9255
9256 reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
9257 arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
9258
9259 reg_len = strlen(reg_name);
9260 arg_len = strlen(arg_name);
9261
9262 /* Exactly one of the two type names may be suffixed with ___init, so
9263 * if the strings are the same size, they can't possibly be no-cast
9264 * aliases of one another. If you have two of the same type names, e.g.
9265 * they're both nf_conn___init, it would be improper to return true
9266 * because they are _not_ no-cast aliases, they are the same type.
9267 */
9268 if (reg_len == arg_len)
9269 return false;
9270
9271 /* Either of the two names must be the other name, suffixed with ___init. */
9272 if ((reg_len != arg_len + pattern_len) &&
9273 (arg_len != reg_len + pattern_len))
9274 return false;
9275
9276 if (reg_len < arg_len) {
9277 search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
9278 cmp_len = reg_len;
9279 } else {
9280 search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
9281 cmp_len = arg_len;
9282 }
9283
9284 if (!search_needle)
9285 return false;
9286
9287 /* ___init suffix must come at the end of the name */
9288 if (*(search_needle + pattern_len) != '\0')
9289 return false;
9290
9291 return !strncmp(reg_name, arg_name, cmp_len);
9292}
9293
9294#ifdef CONFIG_BPF_JIT
9295static int
9296btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
9297 struct bpf_verifier_log *log)
9298{
9299 struct btf_struct_ops_tab *tab, *new_tab;
9300 int i, err;
9301
9302 tab = btf->struct_ops_tab;
9303 if (!tab) {
9304 tab = kzalloc(offsetof(struct btf_struct_ops_tab, ops[4]),
9305 GFP_KERNEL);
9306 if (!tab)
9307 return -ENOMEM;
9308 tab->capacity = 4;
9309 btf->struct_ops_tab = tab;
9310 }
9311
9312 for (i = 0; i < tab->cnt; i++)
9313 if (tab->ops[i].st_ops == st_ops)
9314 return -EEXIST;
9315
9316 if (tab->cnt == tab->capacity) {
9317 new_tab = krealloc(tab,
9318 offsetof(struct btf_struct_ops_tab,
9319 ops[tab->capacity * 2]),
9320 GFP_KERNEL);
9321 if (!new_tab)
9322 return -ENOMEM;
9323 tab = new_tab;
9324 tab->capacity *= 2;
9325 btf->struct_ops_tab = tab;
9326 }
9327
9328 tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
9329
9330 err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
9331 if (err)
9332 return err;
9333
9334 btf->struct_ops_tab->cnt++;
9335
9336 return 0;
9337}
9338
9339const struct bpf_struct_ops_desc *
9340bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
9341{
9342 const struct bpf_struct_ops_desc *st_ops_list;
9343 unsigned int i;
9344 u32 cnt;
9345
9346 if (!value_id)
9347 return NULL;
9348 if (!btf->struct_ops_tab)
9349 return NULL;
9350
9351 cnt = btf->struct_ops_tab->cnt;
9352 st_ops_list = btf->struct_ops_tab->ops;
9353 for (i = 0; i < cnt; i++) {
9354 if (st_ops_list[i].value_id == value_id)
9355 return &st_ops_list[i];
9356 }
9357
9358 return NULL;
9359}
9360
9361const struct bpf_struct_ops_desc *
9362bpf_struct_ops_find(struct btf *btf, u32 type_id)
9363{
9364 const struct bpf_struct_ops_desc *st_ops_list;
9365 unsigned int i;
9366 u32 cnt;
9367
9368 if (!type_id)
9369 return NULL;
9370 if (!btf->struct_ops_tab)
9371 return NULL;
9372
9373 cnt = btf->struct_ops_tab->cnt;
9374 st_ops_list = btf->struct_ops_tab->ops;
9375 for (i = 0; i < cnt; i++) {
9376 if (st_ops_list[i].type_id == type_id)
9377 return &st_ops_list[i];
9378 }
9379
9380 return NULL;
9381}
9382
9383int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
9384{
9385 struct bpf_verifier_log *log;
9386 struct btf *btf;
9387 int err = 0;
9388
9389 btf = btf_get_module_btf(st_ops->owner);
9390 if (!btf)
9391 return check_btf_kconfigs(st_ops->owner, "struct_ops");
9392 if (IS_ERR(btf))
9393 return PTR_ERR(btf);
9394
9395 log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
9396 if (!log) {
9397 err = -ENOMEM;
9398 goto errout;
9399 }
9400
9401 log->level = BPF_LOG_KERNEL;
9402
9403 err = btf_add_struct_ops(btf, st_ops, log);
9404
9405errout:
9406 kfree(log);
9407 btf_put(btf);
9408
9409 return err;
9410}
9411EXPORT_SYMBOL_GPL(__register_bpf_struct_ops);
9412#endif
9413
9414bool btf_param_match_suffix(const struct btf *btf,
9415 const struct btf_param *arg,
9416 const char *suffix)
9417{
9418 int suffix_len = strlen(suffix), len;
9419 const char *param_name;
9420
9421 /* In the future, this can be ported to use BTF tagging */
9422 param_name = btf_name_by_offset(btf, arg->name_off);
9423 if (str_is_empty(param_name))
9424 return false;
9425 len = strlen(param_name);
9426 if (len <= suffix_len)
9427 return false;
9428 param_name += len - suffix_len;
9429 return !strncmp(param_name, suffix, suffix_len);
9430}